Disapproving noises heard at university party (5-2)
I believe the answer is:
booze-up
'party' is the definition.
(alcohol-fuelled party)
'disapproving noises heard at university' is the wordplay.
'disapproving noises' becomes 'boos' (as in boos from a crowd).
'heard' indicates a 'sounds like' (homophone) clue.
'at university' becomes 'up' (slang term meaning at university).
'boos' is a homophone of 'booze'.
'booze'+'up'='BOOZE-UP'
(Other definitions for booze-up that I've seen before include "Drinking spree" , "Bout of serious drinking" , "Heavy drinking session" .)