Green’s Dictionary of Slang

(UK black) to hit, to smash.

1999		(con. 1979–80) A. Wheatle Brixton Rock (2004) 100: I’m going to kuff the window, hol’ the goods and chip to a brethren’s house.
2001		(con. 1981) A. Wheatle East of Acre Lane 283: Sharon kuffed ’im wid a shoe heel.