Cheese having fine character from its source (4)
I believe the answer is:
feta
'cheese' is the definition.
(I've seen this before)
'fine character from its source' is the wordplay.
I cannot really see how this works, but
'fine' could be 'f' (abbreviation) and 'f' is present in the answer.
'character' could be 'eta' (eta is a kind of character) and 'eta' is located in the answer.
No letters remain.
This explanation may well be incorrect...
'having' acts as a link.
(Other definitions for feta that I've seen before include "Low-fat cheese" , "Salty goat or sheep milk cheese" , "Greek dairy product" , "White Greek cheese" , "Greek cheese from goat or sheep milk" .)