Green’s Dictionary of Slang

cop adj.

[cop n.1 (1)]

pertaining to the police or police culture.

[US]R.L. Bellem ‘Ruby Ransom’ Hollywood Detective Dec. [Internet] Nabbing burglars is a cop job.
[US]W.P. McGivern Big Heat 67: He was acting queerly, ignoring some basic cop-rules.
[US]E.K. Walker ‘Harlem Transfer’ in King Black Short Story Anthol. (1972) 50: See that cop captain up there.
[Aus] in K. Gilbert Living Black 30: As soon as they’ve seen the cop car, others are dashing over to report about so ’n so.
[Aus]L. Redhead Peepshow [ebook] My 1967 Ford Futura shuddered to a halt next to the cop car.
[Aus] G. Johnstone ‘No Through Road’ in Crime Factory: Hard Labour [ebook] The sight of a cop car or paddy wagon bringing him home [...] was a regular occurrence.