Green’s Dictionary of Slang

knock it off v.

[knock off v. (1a)]

1. to stop doing something.

[UK]T. Hughes Tom Brown at Oxford (1880) 97: It’s very plucky of him, but I do think he’s a great fool not to knock it off now till he has passed.
[US]H. Hapgood Autobiog. of a Thief 330: The supply was soon exhausted, and I saw that the only thing to do was to knock it off entirely.
[US]R. Chandler Long Good-Bye 149: ‘Look,’ I said. ‘Shove it. Knock it off. They’re no different from anybody else.’.
[US]N. Heard Howard Street 39: ‘Awright now,’ Bill commanded, ‘y’all bitches knock it off.’.
[US](con. 1960s) D. Goines Black Gangster (1991) 34: ‘Knock it off,’ Prince interrupted.
[US](con. 1965) W. Terry Bloods (1985) 3: Better knock that shit off, boy.
[US] Tarantino & Avery Pulp Fiction [film script] 26: I’d knock that shit off if I was you.
[US]K. Huff A Steady Rain I i: Will you effing knock it off, Denny!?

2. to complete or dispose of something easily or quickly.

[UK]I. Welsh Trainspotting 175: The Rent Boy knocks it oaf!

3. see knock off v. (2c)