To work very hard; to put in a lot of effort.
hard at work
Labouring with great effort and diligence; working hard.
put a shift in
To work hard; to make an effort
apply oneself
Synonym of strive: to work hard, to complete an activity with good eff …
elbow grease
Effort or hard work, especially physical work involving repeated motio …
bust ass
To work hard, especially when trying to achieve a goal.
bust one's butt
To work exceptionally hard.