Insult's even head? (3)
I believe the answer is:
nut
'head?' is the definition.
(informal term for somebody's head)
'insult's even' is the wordplay.
'even' means one should take alternating letters (letters in even-numbered positions are used).
The alternate letters of 'insults' are 'NUT'.
(Other definitions for nut that I've seen before include "Mechanical fastener" , "Vegetarian food" , "something turned when making fast > food" , "Crank" , "Fanatical enthusiast" .)