They're edible, like bananas (4)
I believe the answer is:
nuts
'bananas' is the definition.
(as in crazy)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for nuts that I've seen before include "Crazy (sl.)" , "'Here we go gathering . . . . In May'" , "Got a screw loose" , "One eats these" , "Bolt securers" .)