Function as political group? (5)
I believe the answer is:
party
This clue is a double definition.
'function' is the first definition.
(I've seen this before)
'political group?' is the second definition.
(I've seen this before)
'as' acts as a link.
(Other definitions for party that I've seen before include "Festivity" , "festive" , "Group gathered together for pleasure" , "Political group - celebration" , "Celebratory social gathering" .)