Having gold, a fellow can be generous (5)
I believe the answer is:
donor
'generous' is the definition.
(I've seen this in another clue)
'having gold a fellow' is the wordplay.
I cannot really see how this works, but
'gold' could be 'or' ('or' is the heraldic name for gold) and 'or' is found within the answer.
'fellow' could be 'don' (both can mean an academic) and 'don' is present in the answer.
No letters remain.
This explanation may well be incorrect...
'can be' is the link.
Can you help me to learn more?
(Other definitions for donor that I've seen before include "One who dishes out" , "Sponsor" , "One who gives blood, for instance" , "patron" , "One contributing" .)