Social occasions for roving pirates (7)
I believe the answer is:
parties
'social occasions' is the definition.
(party is a kind of social occasion)
'roving pirates' is the wordplay.
'roving' is an anagram indicator.
'pirates' with letters rearranged gives 'PARTIES'.
'for' is the link.
(Other definitions for parties that I've seen before include "Fun affairs for political groups" , "Celebrations" , "Celebrates" , "Social gatherings" , "They may be thrown" .)