Irritate insect lover (7)
I believe the answer is:
gallant
'lover' is the definition.
(I've seen this before)
'irritate insect' is the wordplay.
'irritate' becomes 'gall' (galling is a kind of irritating).
'insect' becomes 'ant' (ant is a kind of insect).
'gall'+'ant'='GALLANT'
(Other definitions for gallant that I've seen before include "lover" , "Flirt" , "Brave and honourable" , "Dandy" , "Charmingly attentive to ladies" .)