Unsavoury character a cop let off (7)

I believe the answer is:

polecat

I'm a little stuck... Click here to teach me more about this clue!

'unsavoury character' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.

'a cop let off' is the wordplay.
'off' indicates an anagram.
'a'+'cop'+'let'='acoplet'
'acoplet' is an anagram of 'POLECAT'.

Can you help me to learn more?

(Other definitions for polecat that I've seen before include "Beast related to weasel" , "weaselly creature" , "Smelly American mammal" , "Weasel-like creature" , "Smelly animal" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.