Preen Oscar for university ball (6)
I believe the answer is:
dollop
'ball' is the definition.
(a dollop is a ball or blob of something)
I cannot understand how the rest of the clue works.
(Other definitions for dollop that I've seen before include "serving food, perhaps" , "Shapeless mass of soft food" , "Squidgy lump (of food)" , "Rough lump" , "Semisolid lump" .)