Decline to vote (7)
I believe the answer is:
abstain
'decline to vote' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for abstain that I've seen before include "not come down on either side" , "Desist" , "'Refrain from, voting or eating, say (7)'" , "Spare" , "Formally decline to vote" .)