Clown fanatic becomes fair target (7)
I believe the answer is:
coconut
'fair target' is the definition.
(I've seen this before)
'clown fanatic' is the wordplay.
'clown' becomes 'coco' (Nicolai Poliakoff aka Coco the Clown).
'fanatic' becomes 'nut' (I've seen this in another clue).
'coco'+'nut'='COCONUT'
'becomes' is the link.
(Other definitions for coconut that I've seen before include "Large seed; head" , "Hairy, milk-containing fruit of the palm" , "Flesh" , "Seed of a tropical palm" , "Hard-shelled fruit of palm tree with white lining" .)