Mad for fruit (7)
I believe the answer is:
bananas
This clue is a double definition.
'mad' is the first definition.
(I've seen this in another clue)
'fruit' is the second definition.
(I've seen this before)
'for' is the link.
(Other definitions for bananas that I've seen before include "bats" , "nutty" , "Crazed" , "off 27 [TROLLEY]" , "Fruit - nuts" .)