One giving fellow at university gold (5)
I believe the answer is:
donor
'one giving' is the definition.
(someone who donates)
'fellow at university gold' is the wordplay.
'fellow at university' becomes 'don' (don can mean an academic - especially at Oxbridge).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'don'+'or'='DONOR'
(Other definitions for donor that I've seen before include "One who gives something" , "Subscriber" , "Sponsor" , "One giving to a cause" , "One who gives blood, for instance" .)