Dilettante couple enter a university run (7)
I believe the answer is:
amateur
'dilettante' is the definition.
(I've seen this in another clue)
'couple enter a university run' is the wordplay.
'couple' becomes 'mate' (synonyms).
'enter' is an insertion indicator.
'university' becomes 'u' (abbreviation for university).
'run' becomes 'r' (cricket abbreviation).
'a'+'u'='au'
'mate' going inside 'au' is 'amateu'.
'amateu'+'r'='AMATEUR'
(Other definitions for amateur that I've seen before include "Fancier" , "incompetent" , "Unpaid performer" , "He's not professional" , "Unpaid player" .)