A fellow accepts them from the devil (5)
I believe the answer is:
demon
'the devil' is the definition.
(synonyms)
'a fellow accepts them' is the wordplay.
'a fellow' becomes 'don' (both can mean an academic).
'accepts' indicates putting letters inside.
'them' becomes 'em' (abbreviation).
'don' going around 'em' is 'DEMON'.
'from' acts as a link.
(Other definitions for demon that I've seen before include "beast" , "Imp" , "Inspiring force" , "Monster" , "Fiend, devil" .)