knock off -
write quickly; "She dashed off a note to her husband saying she would not be home for supper"; "He scratched off a thank-you note to the hostess"
knock off -
To bump or hit so that something falls off.
knock off -
To quit; stop doing work or other activity. The term originated from the practice aboard slave galleys to have a man beat time for the rowers by knocking on a block or drum; when he stopped, the rowers could rest.