Browsing
Idioms starting with O
438 expressions
oat opera
A film or novel depicting adventures of characters in the American Old West; a western.
odd and curious
On the Isle of Man, the common or general man.
odd duck
An unusual person, especially one with an idiosyncratic personality or peculiar behavioral…
odd fish
An unusual thing or eccentric person.
odds and ends
Miscellaneous things; oddments
odds and sods
Miscellaneous items.
of a
on every; in the (followed by a noun indicating a certain time)
of a kind
Of the same type or character.
of a piece
Of the same kind.
of age
Having existed for a certain period of time; used in referring to a person's age.
of all loves
For the sake of all love; by all means.
of all people
Especially; more than other people
of all places
Surprisingly.
of all things
Especially; more than other things.
of an
Indicates a more or less habitual activity during the given part of the day.
of choice
preferred above others.
of late
In the recent past; recently; lately.
of one mind
Having the same viewpoint, opinion, or attitude; in agreement.
of sorts
Resembling; similar to; in a way; partially or not entirely.
of sound mind
sane, rational, maintaining one's mental capability to act reasonably.
of the deepest dye
Of the worst or most extreme sort or type.
of the first water
Of a diamond or other gemstone, of the highest quality or excellence.
of the same leaven
Of a kind, cut from the same cloth.
of the same stripe
Of the same kind; having the same opinion or viewpoint.
of two minds
Undecided or unsure; equivocating; conflicted in one's opinions.
off and running
Launched or launching vigorously into a course of action.
off balance
surprised; perplexed
off board
Not on or in a means of transportation.
off chance
A possibility that is not likely or probable.
off one's block
Crazy; insane.
off one's box
Stoned or intoxicated.
off one's dot
Mad; insane.
off one's feed
Rather unwell, especially with a reduced or altered appetite; somewhat disoriented or disc…
off one's game
Performing in any activity below one's usual level; behaving in an irregular, inept, or aw…
off one's hinge
Alternative form of off one's hinges.
off one's hinges
Unstable or irrational; crazy.
off one's nut
Insane, crazy.
off one's own bat
At one's own instigation, of one's own accord.
off one's tits
Heavily intoxicated; under the influence of alcohol or drugs.
off one's tree
Crazy; unhinged; irrational.
off one's trolley
Having gone mad; insane.
off pat
Synonym of down pat.
off the back foot
From a defensive position.
off the bat
From the start; immediately; right away.
off the beaten path
In a secluded location; in or to a place which is not frequently visited or not widely kno…
off the beaten track
In or to a place or places not commonly visited.
off the deep end
Crazy, erratic, or irrational.
off the face of the earth
Used to emphasize the state of cessation, destruction, termination, etc.
off the grid
In or into a clandestine or isolated situation or place, especially one in which public co…
off the hook
Performing extraordinarily well.
off the radar
Unlikely to happen or be important in the near future, or tending to escape detection or a…
off the rails
In an abnormal manner, especially in a manner that causes damage or malfunctioning.
off the reservation
Violating rules or decorum; out of bounds.
off the scale
Far in excess of what is normal or measurable.
off the top of one's head
In an extemporaneous manner; without careful thought, preparation, or investigation.
off the wagon
No longer maintaining a program of self-improvement or abstinence from an undesirable habi…
off to the races
In or into a process of energetic engagement in some activity; in or into a phase of consp…
offer affordances
To give elbow room or leeway (for something to happen).
offer one can't refuse
An offer from one side in a transaction with terms so attractive that the other side is al…
offer one's condolences
To offer sympathy to someone who has recently experienced the loss of a loved one.
offer up
To give (thanks, praise) to God.
Officer Friendly
A police officer.
oh dark hundred
Some unspecified hour in the early morning (implies an unpleasant time to be awake)
oh dark thirty
Some unspecified hour in the early morning (implying an unpleasant time to be awake).
oh my
oh my God
oh my goodness gracious
Oh my God.
oh my gosh
oh my God!
oh well
An expression of mild disappointment or resignation: too bad; it's a pity; what can you do…
oil and water
Two things which are incapable of mixing or coexisting harmoniously with each other.
oil burner
A device whose operation causes apparent combustion of lubricating oil.
oil trash
An uncultured, rowdy roughneck employed in the petroleum industry, especially a "white tra…
old as the hills
Extremely old.
old boy network
A presumed unacknowledged system of association between childhood friends (especially thos…
old chestnut
A well-worn story.
old enough to vote
Old; decrepit (said especially of an inanimate object).
old fart
An elderly person, especially one who holds old-fashioned views.
old flame
A previous boyfriend or girlfriend; a former romantic or sexual partner, especially one fo…
old fogey
An old and overly conservative person.
old hand
A person who is experienced at a certain activity.
old hat
Very familiar and unoriginal; common, hackneyed, out of date.
old head on young shoulders
Alternative form of good head on one's shoulders.
old money
Families that have been wealthy for generations or members of such families.
old salt
A seasoned sailor, especially one who is hardy and forthright in manner.
old saw
A cliché, saying, or overused expression, especially a proverb or maxim.
Old School
Alternative letter-case form of old school (“having conservative or traditional views on C…
old song
A trifle; nothing of value.
old stager
A veteran; an experienced person.
old stick
A person.
old wine in a new bottle
An existing concept or institution offered as though it were a new one.
old-fashioned look
A glance of disdain or disapproval.
oll korrect
All right; okay.
on a day-to-day basis
Occurring as part of a daily routine.
on a dime
Within a very short distance; especially, with agile precision in a very confined space an…
on a first-name basis
Having enough familiarity with another person to call them by their first name, as opposed…
on a full stomach
Directly after eating; straight after a meal.
on a kick
Having a period of enthusiasm towards some activity.
on a lark
In a frolicky or frivolous manner; on a whim.
on a losing wicket
in a no-win situation.
on a plate
Within easy reach; easily achieved.
on a regular basis
Regularly; occurring in regular time intervals or patterns.
on a shoestring
On a very tight budget; with few resources or little money.
on a silver platter
Being given something too easily, especially more than one deserves.
on a sixpence
Within a very short distance.
on a tear
Engaged in a continuous, fast-paced procession of actions or events, especially with favor…
on a whim
Without thinking seriously about the consequences.
on account of
Because of, due to, owing to.
on acid
Exaggerated, bizarre or unpredictable.
on all fours
On one's hands and knees.
on an irregular basis
Irregularly, occurring in irregular time intervals or patterns.
on and off
Intermittently.
on another note
announcing a change in a topic or subject
on average
Usually, typically; as a rule; as often as not.
on bad terms
being unfriendly; having bad relations.
on blast
In an embarrassing position from having been publicly denounced or exposed, especially fro…
on board
Joining in or participating.
on cloud nine
In a state of elation; very happy; blissful.
on cloud seven
In a state of elation; very happy; blissful.
on course
Following the intended route.
on demand
When needed or required.
on edge
Tense, nervous; consequently irritable.
on end
without interruption, without stopping, continuously
on eternal patrol
Lost at sea.
on file
Duly submitted, accepted, or recorded.
on fire
Overwhelmed with emotion; beside oneself.
on good terms
Being friendly; having good relations.
on hand
Available; ready; in stock.
on hold
Delayed; postponed; suspended.
on ice
Not being used; temporarily unavailable or suspended; on hold.
on in years
Old; advanced in age.
on its merits
Considering only intrinsic good points and bad points, without prejudice or other consider…
on one's bill
Alone, on one's own.
on one's deathbed
Close to death.
on one's feet
Able to stand; hence, healthy, well, especially after some previous illness.
on one's high horse
Self-righteous; proceeding on the belief one is more correct or proper than others.
on one's last legs
About to die.
on one's lonesome
Alone; without aid or accompaniment.
on one's mind
In one's thoughts, especially persistently or recurrently.
on one's tod
On one's own, alone.
on one's toes
Attentive, active, busy or alert.
on one's watch
During the period of time when one is in a position of authority or responsibility.
on opposite sides of the barricades
Holding starkly opposite views on an issue.
on pins and needles
Feeling sharp anticipation or anxiety; in a state of suspense.
on purpose
By design, as opposed to by accident; intentionally; deliberately.
on second thought
After reconsidering; on further consideration.
on sight
Immediately when sighted.
on solid ground
Confident or justified regarding a subject or argument.
on someone's dime
At the monetary expense of the person indicated.
on someone's doorstep
Very nearby.
on someone's hands
Being someone's liability or responsibility; with which someone is lumbered.
on someone's mind
Preoccupying someone; present in someone's thoughts.
on someone's radar
Within someone's awareness, attention or consideration.
on steroids
To a greater degree, exaggerating the characteristics of the previously named object.
on strike
Withholding labor as a protest, in order to effect change in management or government.
on stun
(usually after a plural noun), to a degree that is stunning.
on sufferance
Unwillingly agreed to or barely tolerated.
on talking terms
able to talk with someone, either in general or about the particular topic
on tenterhooks
In a state of (great) apprehension or suspense; on pins and needles; on the rack.
on the anvil
In a state of discussion, formation, or preparation; not yet matured.
on the back burner
Not immediate; inactive; receiving or requiring less than full or regular attention.
on the back foot
in a defensive posture; on the defensive; off balance; at a disadvantage.
on the ball
Alert, active, or attentive; on top of things.
on the beach
Removed or retired from an active shipboard position in the navy or merchant navy.
on the boob
Breastfeeding, nursing at the breast.
on the bounce
consecutively, in succession
on the brain
Obsessively in mind.
on the breadline
In a situation of extreme poverty; relying on food donations or having only enough to surv…
on the bubble
Uncertain of success.
on the button
Exactly, precisely.
on the canvas
In a state of being overwhelmed, defeated, or in a challenging situation.
on the cards
Likely to occur, probable.
on the clock
Working at one's job; occupied in some manner during one's hours of remunerated employment…
on the cuff
On credit, with payment to be made later.
on the cusp
on the point of a significant transformation, ascendance, etc.
on the cutting room floor
Not included in the finalized version of something; deliberately rejected or unintentional…
on the debit side
On the negative or bad side of things.
on the dot
Exactly; precisely, especially of a time of day.
on the double
Rapidly or immediately.
on the down-low
In secret or nearly so, on a need-to-know basis.
on the drum
Money in the form of paper currency or coins, paid immediately at the time and place of a …
on the dry
temporarily refraining from drinking alcohol
on the edge of one's seat
In suspense; waiting eagerly or anxiously for some resolution.
on the face of
Notwithstanding.
on the face of it
Seemingly; to all appearances; as far as can be seen or determined without deeper investig…
on the flip side
On the other hand; conversely.
on the fly
Spontaneously or extemporaneously; done as one goes, or during another activity.
on the fritz
Of an electrical or mechanical appliances, out of order; malfunctioning; broken.
on the front burner
Currently receiving attention.
on the front foot
In a dominant position.
on the game
Working as a prostitute.
on the go
Actively traveling; busy; moving often.
on the gripping hand
from a third point of view
on the heels of
In close pursuit of; close behind.
on the high rope
Elated.
on the high ropes
In an elated or highly excited mood.
on the hoof
Alive; embodied in a living animal (including a human); in working order.
on the hook
In debt; obligated to pay or provide; liable; responsible or blamed.
on the horn
On the telephone.
on the horns of a dilemma
Facing a choice between two equally undesirable alternatives.
on the hush
Secretly; in secret.
on the ladder
On a property ladder, owning property.
on the level
Honest(ly), sincere(ly), straightforward(ly), fair(ly).
on the lines of
Similar to, but not exactly equal.
on the loose
Not incarcerated or in captivity; not under control.
on the mark
Precisely accurate; correct or appropriate.
on the mat
To be reprimanded or called to account by someone in authority.
on the money
In the correct position; on target; precisely accurate; accurately.
on the move
Changing location; in motion.
on the nose
Exact; precise; appropriate.
on the one hand
From one point of view.
on the other hand
From another point of view.
on the other side of
After.
on the outs
On unfriendly terms; estranged.
on the outside, looking in
Excluded from a group, process, or opportunity, and feeling downhearted as a result.
on the pill
Using oral contraceptives.
on the plus side
Positively; from a favorable view or perspective.
on the point of
Very near to; ready to; just about to; such that something is imminent.
on the prowl
Hunting or seeking; prowling about.
on the Q.T.
Quietly; in a secretive manner; clandestinely.
on the rack
To be under great stress, anxiety, or physical strain.
on the radar
Likely to happen, or be important in the near future or tending to attract attention.
on the rag
Menstruating.
on the rails
In working order, functioning properly.
on the rampage
behaving violently or rioting
on the ready
Well-prepared or set to initiate.
on the receiving end
Being the victim of an unpleasant action.
on the right side of history
Aligning with positions or actions that future generations will morally endorse as just or…
on the rise
rising; becoming greater in number or magnitude.
on the run
Fleeing.
on the same page
In broad agreement or sharing a common general understanding or knowledge (common in offic…
on the same wavelength
Thinking in the same way; having similar thought processes (in general).
on the shelf
Laid aside.
on the side of the angels
Fighting for or supporting that which is good, just, or benevolent.
on the skids
In decline; going downhill; in trouble.
on the sly
Slyly, in an inconspicuous manner, so as not to be seen; secretly; stealthily.
on the spot
At that very moment.
on the square
Honest and open.
on the stocks
in progress, underway
on the street
Without a home; without the means to afford good shelter.
on the table
Open or available for further attention or action.
on the toss of a coin
Left to pure chance; based on a flippant metric.
on the trot
Successively, in succession; one after the other.
on the up
Rising; becoming greater in number or magnitude.
on the up-and-up
Legitimate; honest; upright.
on the uptake
In understanding or in the ability to absorb new information; especially in the phrases "q…
on the wagon
Abstaining from drinking any alcoholic drink, usually in the sense of having given it up (…
on the wane
in a period of decrease or decline
on the warpath
Very angry or upset and eager for confrontation.
on the way
Coming; approaching.
on the whole
For the most part; apart from some insignificant details.
on the wrong side of history
Having policies or practices that are perceived as not progressive or enlightened; behavin…
on the wrong side of the blanket
Born illegitimately, outside of wedlock.
on thin ice
Dangerously, hazardously, delicately.
on this score
In reference to or with regard to the subject that is being discussed.
on top
In a dominant position.
on top of
In addition to something else.
on top of the world
Delighted; ecstatic; exceptionally pleased, happy, or satisfied.
on track
Proceeding as planned, as expected, or in a manner consistent with an established pattern.
on what score
For what reason? In regard to what?
on with you
An expression of dismissal or contempt directed at someone.
on yer bike
go away! scram!
once again
Again, once more, one more time.
once and for all
Conclusively, finally, permanently.
once in a blue moon
Very rarely; very infrequently.
once in a purple moon
Extremely rarely; almost never.
once in a while
Occasionally; sometimes.
once or twice
A small, indefinite number of times.
one after another
In single file.
one age with
The same age as.
one and all
The entire set of persons or things within a given domain, considered both as separate ind…
one and only
Only love, sole sweetheart.
one and the same
The selfsame person or thing. Used to emphasize the identity or equivalence of two things.
one big happy family
A group of people who get along well together.
one brick short of a full load
Stupid.
one could do it in one's sleep
Said of something that can be done very easily or effortlessly.
one could hear a pin drop
Extremely quiet, for example, as during a lull in a normally bustling place or scene, or a…
one fell swoop
One stroke; one action or event that achieves or accomplishes many results.
one flesh
Two people united by marriage.
one for the road
A final drink before one leaves.
one hundred and one
A great many; numerous.
one in the eye for
An event or achievement which is unpleasant for someone, especially for those who consider…
one man and his dog
Almost nobody; very few people.
one moment
Stop; wait; hold on. Used to interrupt speech or proceedings so that one can make a commen…
one more again
One more time; once again.
one of His Majesty's bad bargains
An incapable (sick, etc) or incompetent soldier.
one of those things
An unfortunate, but unavoidable, event.
one side
A direct, somewhat impolite demand to ask someone to move out of the way.
one small step for man, one giant leap for mankind
(used imitatively) A cliché used to exaggerate an accomplishment or milestone.
one step ahead
maintaining a slight advantage; continuing to lead
one step forward, two steps back
A situation in which progress is more than offset by adverse developments.
one thing led to another
From one event, a series of insignificant steps resulted in another event.
one thing or another
Various different events, tasks, duties, or contributing elements.
one too many
One or more servings too many of alcohol, leading to drunkenness.
one up
To outdo, to perform something slightly better than a competitor's prior effort.
one-hit wonder
A recording artist known for only one hit song, especially after failing at subsequent att…
one-horse race
An election campaign or other competitive situation in which only one competitor is entere…
one-horse town
A very small town, especially one of a rural nature and offering very few or no attraction…
one-man band
An organisation or business that is effectively run by only one person.
one-night stand
A single sexual encounter between two individuals, where at least one of the partners has …
one-track mind
That said to be possessed by someone who is obsessed with something or only able to think …
one-trick pony
A person or group noteworthy for only a single achievement, skill, or characteristic.
one-way ticket to Palookaville
Something that results in failure or obscurity, with no chance at redemption; a dead end.
one's back is up
One is offended or angry.
one's bark is worse than one's bite
One acts in a threatening way but is relatively harmless.
one's blood is up
One is very angry.
one's cake is dough
One's actions have failed to achieve any success or make any progress.
one's days are numbered
Some period of time, such as a term of employment or a lifetime, is coming to an end.
one's heart in one's mouth
A state of nervousness.
one's heart out
With great effort or enthusiasm.
one's jig is up
Alternative form of the jig is up [for one].
one's lips are sealed
One will not tell anyone else; one is keeping a secret.
one's name is mud
One is unpopular, in disgrace or embroiled in scandal; one's reputation is tarnished.
one's ship comes in
One makes or comes into possession of a significant amount of money.
one's socks off
With a large amount of effort or intensity.
one's word is law
One's requests or orders must be fulfilled.
only game in town
The only opportunity, activity, or resource available.
only time will tell
Alternative form of time will tell.
onward and upward
Alternative form of onwards and upwards.
onwards and upwards
On to greater things.
open a can of whoop ass
A good-humored threat of physical harm.
open book
Something whose salient aspects are obvious or easily interpreted.
open doors
To lead to opportunities or social advantages.
open field
A situation with no obstacles or limitations; a clear opportunity to act freely or without…
open fire
To begin firing (weapons) at something or someone.
open invitation
A situation or action that tempts someone to do something which would typically yield an u…
open one's legs
Synonym of put out (consent to having sex).
open one's mind
To become receptive to new ideas and perspectives.
open one's mouth
to speak
open Pandora's box
To perform an action that causes problems to appear which did not exist beforehand, or wer…
open season
A situation or period in which some activity is routinely carried on.
open someone's eyes
To make someone aware of something they did not know or fully understand before; to enligh…
open the batting
By extension, to commence proceedings (in general, not just in cricket).
open the door
To allow access or facilitate.
open the floodgates
To allow some action to proceed more swiftly or to a greater extent.
open the kimono
To reveal confidential information, especially details of one's business operations.
open the schools
Expressing that someone is wrong or misinformed, especially where something should be wide…
open wide
To open one's mouth wide, to gape.
open-door policy
A policy or usual practice, by a person in authority, of permitting subordinates or consti…
opening of an envelope
Any kind of event or activity that may contribute to one's self-promotion or visibility in…
opinions are like assholes
Everyone has opinions, and most people's opinions are of exceedingly poor quality.
opposite number
A person who holds a position in an organization, sports team, or the like, that correspon…
or else
Implies an unspecified threat if a preceding command is not fulfilled.
or something
Or something like that. Used to indicate the possibility that the preceding word or phrase…
or what
Or something else; allows for the existence of an unexpressed alternative to what was said…
or words to that effect
used to indicate a paraphrase or the chance of an error in the details of reported speech.
orange wine
A type of wine made from white wine grapes whose skins are not removed.
oranges with oranges
Synonym of apples to apples.
Oreo cookie
A black person that appears to the community to embody the social and cultural features of…
ostrich policy
The tendency to ignore obvious problems and pretend they do not exist; ostrichism.
other end of the ball
used after discussing either offense or defense to imply the other.
other fish in the sea
Other goals or objectives to pursue.
other half
A spouse or a significant other.
other head
The glans of the penis.
other man
A man who is romantically involved with someone (usually a woman) already in a committed r…
other side
The afterlife, as a supernatural realm inhabited by spirits of deceased people.
other than
Except, besides.
other woman
A woman who is romantically involved with someone (usually a man) already in a committed r…
otherwise engaged
busy doing something else
our era
Anno Domini; the current date era beginning approximately 2000 years ago in the Gregorian …
out and about
Traveling; out; moving; engaged in day-to-day activities requiring travel.
out for blood
With the intent of killing or severely injuring somebody (especially out of revenge).
out loud
Using the voice; not silently; aloud.
out of a nightmare
Terrifying; shocking.
out of bounds
Where one is prohibited to enter.
out of central casting
Conforming to the stereotypical image of a particular type of person or group.
out of character
Inconsistent with someone's personality, disposition, or usual expected behaviour.
out of collar
Unemployed; out of work.
out of date
Too old to be used; not current; invalid; having expired.
out of fix
Wrong, broken, nonfunctional
out of frame
Not in correct order or condition; irregular; disarranged.
out of gas
Tired; lacking energy or motivation.
out of harness
Synonym of out of collar (“unemployed; out of work”).
out of house and home
In a manner that deprives someone of a dwelling place or some usage thereof.
out of kilter
Askew, disturbed; not adjusted or working properly; out of order.
out of line
Inappropriate or unsuitable, especially by reason of being unmannerly or indelicate.
out of luck
Experiencing a temporary misfortune.
out of nowhere
In an unexpected or inexplicable manner of arrival or occurrence.
out of one's box
Crazy; unhinged; irrational.
out of one's depth
In a situation which one is poorly prepared or unprepared to handle.
out of one's element
In a situation which is unsuitable, unfamiliar, or unenjoyable.
out of one's face
Drunk; intoxicated; inebriated.
out of one's league
In a situation in which one is mismatched with one or more others whose accomplishments, p…
out of one's mind
Insane, crazy.
out of order
Out of normal sequence.
out of place
Not in the proper arrangement or situation.
out of pocket
Lacking funds, or suffering a financial loss; broke.
out of proportion
Not in a proper or pleasing relation to other things, especially in terms of size.
out of season
Not in a proper season or time; untimely; inopportune.
out of shape
Physically unfit.
out of sight
Not yet attainable.
out of someone's way
Not in the direct route that one would normally use.
out of sorts
Irritable or somewhat unwell, with vague medical symptoms.
out of spoons
Out of physical or mental energy.
out of the blue
Unexpectedly; without warning or preparation.
out of the chute
At the start, immediately.
out of the frying pan, into the fire
Move or get from an already bad situation to a worse one; end up in a worse situation when…
out of the gate
At or from the very beginning; from the outset; immediately upon starting.
out of the loop
Not informed, up-to-date, or current; not included in a process or discussion.
out of the ordinary
Unusual or exceptional, especially for the better.
out of the picture
Not included in the matter being planned or under consideration; not a factor or participa…
out of the question
Not remotely possible.
out of the running
No longer in a competition; eliminated from consideration.
out of the way
So as not to obstruct or hinder; not in the way.
out of the woods
Out of peril; likely to recover or prevail over trouble; finished with the worst or most t…
out of thin air
From nowhere or nothing; from a non-existent or unknown source.
out of this world
Of exceptionally high quality; wonderful; marvelous.
out of touch
No longer maintaining contact or communications.
out of wedlock
Of parents not legally married.
out of whack
Wrong, broken; specifically
out on a limb
In a risky, precarious, daring, or uncompromising position, especially one outside of the …
out on one's feet
Standing erect but not consciously aware of one's surroundings, or only minimally aware, a…
out on the tiles
Out for a night on the town.
out sick
Absent from work due to an illness.
out the window
Made obsolete; altered drastically as a result of situational change.
out to lunch
Clueless, inattentive, or careless.
out-paramour the Turk
To have many romantic affairs.
outpope the Pope
To act as a more authentic member of a group than one who is actually a member of the grou…
outrun the constable
To spend more than one's income; to get into debt.
outside chance
A small likelihood; a remote possibility.
outside job
A crime or other illicit action committed by an individual not connected or associated wit…
outside the box
Beyond the bounds of convention or normal practice.
outside world
The rest of the world outside of some closed, restricted, or remote environment.
over a barrel
In a disadvantageous or helpless situation, especially one in which one may be controlled …
over and out
A fictitious proword used to end a conversation over push-to-talk radio.
over and over again
Repeatedly; again and again; many times.
over my dead body
Under no circumstances; absolutely not.
over nine thousand
Off the charts; through the roof (beyond expectations).
over one's head
More complex or confusing than one can understand; beyond one’s comprehension.
over one's skis
Acting or speaking prematurely; getting ahead of oneself.
over the hill
Of a person, old, past the prime of life.
over the hills and far away
Far away; not near.
over the hump
Past the most challenging part of something.
over the line
Beyond the level of what is acceptable.
over the moon
Delighted, thrilled.
over the top
Beyond normal, expected, or reasonable limits; outrageous.
over the transom
Of a work submitted for publication, unsolicited.
overstep the mark
To behave in an unacceptable or morally reprehensible way.
ox is in the ditch
This is a big problem; there is unavoidable or demanding work ahead.
oxygen burning
The nucleosynthesis process, subsequent to carbon burning, in which neon disintegrates to …