Forever holding vote outside (8)
I believe the answer is:
external
'outside' is the definition.
(synonyms)
'forever holding vote' is the wordplay.
'forever' becomes 'eternal' (I've seen this in another clue).
'holding' indicates putting letters inside.
'vote' becomes 'x' (how votes are marked).
'eternal' placed around 'x' is 'EXTERNAL'.
(Other definitions for external that I've seen before include "abroad" , "Superficial" , "Coming from outside" , "involving foreign nations" , "Lying outside" .)