Jack's a rogue! (5)

I believe the answer is:

knave

This clue is a double definition.

'jack's' is the first definition.
('knave' can be a synonym of 'jack')

'a rogue' is the second definition.
('knave' can be a synonym of 'rogue')

(Other definitions for knave that I've seen before include "Jack - scoundrel" , "one found amongst thieves" , "Rapscallion" , "Yet he may be a diamond" , "[COURT CARD] , maybe" .)

I've seen this clue in the Evening Standard.

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