Down mature fruit first (7)
I believe the answer is:
plumage
'down' is the definition.
'mature fruit first' is the wordplay.
'mature' becomes 'age' (synonyms).
'fruit' becomes 'plum' (plum is a kind of fruit).
'first' is a charade indicator (letters next to each other).
'age' after 'plum' is 'PLUMAGE'.
(Other definitions for plumage that I've seen before include "Cover for diver" , "Bird's covering of feathers" , "Birds' clothing" , "coat" , "A bird's feathers, may be fancy" .)