Reinforce grievance at university (4,2)
I believe the answer is:
beef up
'reinforce' is the definition.
(I know that reinforce is a more specific form of the action beef up)
'grievance at university' is the wordplay.
'grievance' becomes 'beef' (I've seen this in another clue).
'at university' becomes 'up' (slang term meaning at university).
'beef'+'up'='BEEF UP'
(Other definitions for beef up that I've seen before include "buttress" , "Give added strength" , "message poor meat-eaters won't want to hear?" , "Strengthen with cow meat?" , "Give (something) more strength" .)