Say goodbye to a pass at university (5)
I believe the answer is:
adieu
'say goodbye' is the definition.
('goodbye' in French)
'a pass at university' is the wordplay.
'pass' becomes 'die' (as in passing away).
'at' is a charade indicator (letters next to each other).
'university' becomes 'u' (abbreviation for university).
'a'+'die'+'u'='ADIEU'
'to' acts as a link.
(Other definitions for adieu that I've seen before include "Parting greeting" , "Goodbye, mademoiselle" , "Farewell (French)" , "Fare thee well!" , "cheers" .)