KNOCK IT OFF

{v. phr.}, {slang}, {informal} 1. To stop talking about something considered not appropriate or nonsensical by the listener. - Used frequently as an imperative. * /Come on, Joe, knock it off, you're not making any sense at all!/ 2. To cease doing something; to quit. - Heavily favored in the imperative. * /Come on boys, knock it off, you're breaking the furniture in my room!/