Kind of green bananas (5)
I believe the answer is:
genre
'kind' is the definition.
(genre is a kind of kind)
'green bananas' is the wordplay.
'bananas' indicates anagramming the letters (informal term for mad).
'green' with letters rearranged gives 'GENRE'.
'of' acts as a link.
(Other definitions for genre that I've seen before include "Brand" , "Literary type, species" , "Particular style of art or literature, may be green" , "Style (of art/literature)" , "expressive style of music" .)