Cunning to wear the man's suit (6)
I believe the answer is:
hearts
'suit' is the definition.
(I've seen this before)
'cunning to wear the man's' is the wordplay.
'cunning' becomes 'art' (I've seen this before).
'to wear' means one lot of letters goes inside another.
'the man' becomes 'hes' (I've seen this in other clues**).
'art' inserted into 'hes' is 'HEARTS'.
(Other definitions for hearts that I've seen before include "Red playing cards" , "Major suit at cards" , "Scots club nickname; suit" , "See 23" , "Card suits in bodies" .)