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 understand how this works, but
'gold' could be 'or' ('or' is the heraldic name for gold) and 'or' is located in the answer.
'fellow' could be 'don' (both can mean an academic) and 'don' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'can be' acts as a 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" .)