Blow a fair share? (5)
I believe the answer is:
whack
I believe this clue is a double definition.
'blow' is the first definition.
(whack is a kind of blow)
'a fair share?' is the second definition.
(as in a fair whack)
(Other definitions for whack that I've seen before include "ration" , "Strike sharply" , "Strike; share (slang)" , "Punch" , "Hit loudly" .)