Expelled from university, dons went off (4,4)
I believe the answer is:
sent down
'expelled from university' is the definition.
(I've seen this before)
'dons went off' is the wordplay.
'off' indicates anagramming the letters.
'dons'+'went'='donswent'
'donswent' is an anagram of 'SENT DOWN'.
(Other definitions for sent down that I've seen before include "locked up" , "Expelled from university" , "imprisoned" , "Rusticated" .)