Fruit eaten by humble monks (5)
I believe the answer is:
lemon
'fruit' is the definition.
(lemon is a kind of fruit)
'eaten by humble monks' is the wordplay.
'eaten by' indicates a hidden word.
'LEMON' can be found hidden inside 'humble monks'.
(Other definitions for lemon that I've seen before include "Sharp-tasting fruit" , "Dab" , "definitely not a peach" , "Pulsate" , "Fruit high in vitamin C" .)