Cavort at Prom, perhaps (4)
I believe the answer is:
romp
'cavort' is the definition.
(I know that cavort can be written as romp)
'prom perhaps' is the wordplay.
'perhaps' is an anagram indicator.
'prom' is an anagram of 'ROMP'.
'at' is the link.
(Other definitions for romp that I've seen before include "Light-hearted film; easy victory" , "Frisk - gambol" , "Frolic" , "Easy victory; play around energetically" , "Boisterous prank" .)