An insult (7)
I believe the answer is:
affront
'an insult' is the definition.
(synonyms)
This is all the clue.
(Other definitions for affront that I've seen before include "Snub" , "Insult to one's face" , "Offend the modesty or values of (someone)" , "Offend; offence" , "Rant off over insult" .)