Cunning insult for the audience (7)
I believe the answer is:
sleight
'cunning' is the definition.
(I've seen this before)
'insult for the audience' is the wordplay.
'insult' becomes ''slight' (I've seen this before).
'for the audience' indicates a 'sounds like' (homophone) clue (how an audience might hear it).
'slight' sounds like 'SLEIGHT'.
(Other definitions for sleight that I've seen before include "Conjuror uses this" , "Cunning action" , "Artful trick" , "Hits leg (anag) - cunning" , "It's deceiving to the eye" .)