Go crazy in retreat (4)
I believe the answer is:
stab
'go' is the definition.
(both can mean an attempt)
'crazy in retreat' is the wordplay.
'crazy' becomes 'bats' (I've seen this before).
'in retreat' shows that the letters should be reversed in order.
'bats' reversed gives 'STAB'.
(Other definitions for stab that I've seen before include "Thrust at and pierce" , "pink" , "Rough guess; to knife" , "Strike with knife" , "Pierce with pointed weapon" .)