Fellow consumed rejected cheese (4)
I believe the answer is:
feta
'cheese' is the definition.
(I've seen this before)
'fellow consumed rejected' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'consumed' becomes 'ate' (eating is a kind of consuming).
'rejected' says the letters should be written backwards.
'ate' reversed gives 'eta'.
'f'+'eta'='FETA'
(Other definitions for feta that I've seen before include "Greek cheese from goat or sheep milk" , "Soft Greek cheese" , "White and salty goat or sheep cheese" , "Greek 8 across" , "Greek sheep or goats' cheese" .)