Poor stiff at university (4,2)
I believe the answer is:
hard up
'poor' is the definition.
(similar in meaning)
'stiff at university' is the wordplay.
'stiff' becomes 'hard' (similar in meaning).
'at university' becomes 'up' (slang term meaning at university).
'hard'+'up'='HARD-UP'
(Other definitions for hard up that I've seen before include "Impoverished" , "It's not easy to be in straitened circumstances" , "Short of money - it's tough at the top" , "boracic" , "Struggling with budget" .)