Split bananas (7)
I believe the answer is:
cracked
I believe this clue is a double definition.
'split' is the first definition.
(thesaurus)
'bananas' is the second definition.
(both can informally mean mad)
(Other definitions for cracked that I've seen before include "Fractured" , "Having fissures" , "Slangily eccentric - or broken" .)