A nut may split the trophy (8)
I believe the answer is:
crackpot
'a nut' is the definition.
(synonyms)
'split the trophy' is the wordplay.
'split' becomes 'crack' (I've seen this before).
'the trophy' becomes 'pot' (I've seen this before).
'crack'+'pot'='CRACKPOT'
'may' is the link.
(Other definitions for crackpot that I've seen before include "Mad" , "Ridiculous" , "Idiot" , "Nutty" , "Crank" .)