Frolic at Prom, perhaps (4)
I believe the answer is:
romp
'frolic' is the definition.
(I know that frolic can be written as romp)
'prom perhaps' is the wordplay.
'perhaps' indicates an anagram.
'prom' with letters rearranged gives 'ROMP'.
'at' acts as a link.
(Other definitions for romp that I've seen before include "Boisterous prank" , "Frolic" , "High jinks" , "Play in a lively way, like children" , "Lively play during prom" .)