(idiomatic, British spelling) Alternative form of work someone's ass off.

(idiomatic) To maintain one's concentration fixed on one important theme.

(idiomatic) To work especially hard, usually for an extended period.

(idiomatic) To be overly careful in dealing with a person or situation because they get angry or offended very easily; to try very hard not to upset someone or something.

The world, a place where darkness and death are figurative valleys one must walk through as part of the human experience. / A very dangerous place.

(snooker, pool) To pot the cue ball accidentally after hitting the object ball.

(snooker, pool) Of the cue ball: (going) into a pocket, after cannoning another ball.

(snooker, pool) The situation where the cue ball goes into a pocket after striking the object ball.

(idiomatic) To do things in one's own way regardless of societal norms and conventional expectations.

(idiomatic) To lose one's concentration on what is most important.