Real Dictionary

knock off
phrasal verb: If someone knocks someone else off, they kill them.
phrasal verb: If someone knocks something off, they steal it.
phrasal verb: If you knock something off a list or document, you remove it.
phrasal verb: To knock off a house, factory, or shop means to break into it and steal money or property.
phrasal verb: To knock off an amount from a price, time, or level means to reduce it by that amount.
phrasal verb: When you knock off, you finish work at the end of the day or before a break.

knock off in American English
to cease activity, esp. work
to stop working

knock off in British English
to finish work
noun: an illegal imitation of a well-known product