Agile monkey hides fruit (5)
I believe the answer is:
lemon
'fruit' is the definition.
(lemon is a kind of fruit)
'agile monkey hides' is the wordplay.
'hides' indicates a hidden word.
'LEMON' is hidden within 'agile monkey'.
(Other definitions for lemon that I've seen before include "Yellow citrus fruit with acid taste" , "Dab" , "certainly not a plum!" , "Fruit (which is proverbially "the answer")" , "Fruit - useless thing" .)