one's bark is worse than one's bite

all bark and no bite

Full of big talk but lacking action, power, or substance; pretentious.

one's days are numbered

Some period of time, such as a term of employment or a lifetime, is co…

one's back is up

One is offended or angry.

one's lips are sealed

One will not tell anyone else; one is keeping a secret.

one's jig is up

Alternative form of the jig is up [for one].

one's word is law

One's requests or orders must be fulfilled.