Fruit among nuts (5)
I believe the answer is:
mango
'fruit' is the definition.
(type of fruit)
'among nuts' is the wordplay.
'nuts' indicates anagramming the letters (nuts can mean crazy).
'among' with letters rearranged gives 'MANGO'.
(Other definitions for mango that I've seen before include "Yellow-fleshed fruit" , "No, Mag has the odd fruit" , "Ovoid edible fruit" , "Asian fruit" , "fruit-tree" .)