Degree students have big party (4)
I believe the answer is:
ball
'big party' is the definition.
(a ball is a party)
'degree students' is the wordplay.
'degree' becomes 'ba' (Bachelor of Arts).
'students' becomes 'LL' (two abbreviations for learner).
'ba'+'ll'='BALL'
'have' is the link.
(Other definitions for ball that I've seen before include "All-round" , "that one might throw?" , "Throw a dance" , "Squash, say" , "Round object - dance" .)