break off

1. To remove a piece from a whole by breaking or snapping.
2. To become detached by breaking or snapping.
3. To discontinue abruptly.
4. To end abruptly, either temporarily or permanently.
5. To play the first shot in a frame of snooker, billiards or pool.
6. (slang) To give (someone) (something); to allow (someone) to take (something); to grant (someone) a share or portion of (something).