Crossword Genius

Old devil at the police station (4)

Ross

I believe the answer is:

nick

This clue is a double definition.

'old devil' is the first definition.
(I've seen this before)

'the police station' is the second definition.
(slang term)

'at' acts as a link.

(Other definitions for nick that I've seen before include "In the .... of time; just made it" , "jug" , "Small cut or notch" , "Appropriate" , "Catch" .)

I've seen this clue in the Evening Standard.
Want a hint initially instead of a full solution? Install my app