knock off

(verb): To halt one's work or other activity.
(verb): To kill.
(verb): To remove, as a discount or estimate.
(verb): To rob.
(verb): To make a copy of, as of a design.
(verb): To assign (an item) to a bidder at an auction, indicated by knocking on the counter.
(verb): To have sex with.
(verb): To accomplish hastily.
(noun): An imitation of something, particularly a well-known product, usually lower in quality and price than the original.
(noun): A device in a knitting machine to remove loops from the needles.

I think I'll knock off for the evening and go to bed.
The mobsters hired the guy to knock off their enemies.
They agreed to knock off 20% of the price.
They decided to knock off a liquor store downtown.
They send people to the shows in Milan for "ideas", which means knocking off the designs they guess would sell.