Green’s Dictionary of Slang

1. (UK Und.) the practice by corrupt policemen of taking bribes from criminals, to turn a blind eye when necessary, to drop charges, to lose evidence etc.

1977

D. Powis Signs of Crime 179: Copping The criminal practice of receiving corrupt payments or bribes.

2. (US teen) shoplifting.

1991

D. Gaines Teenage Wasteland 104: We [...] went ‘copping’ (shoplifting).