Celebration for political group (5)
I believe the answer is:
party
This clue is a double definition.
'celebration' is the first definition.
(I've seen this in another clue)
'political group' is the second definition.
(a political party)
'for' is the link.
(Other definitions for party that I've seen before include "Shooting weapon" , "Group gathered together for pleasure" , "Political organisation" , "Political group - celebration" , "Social occasion - political group" .)