Refrain from voting (7)
I believe the answer is:
abstain
'refrain from voting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for abstain that I've seen before include "Deny oneself" , "Refrain, forbear" , "Refuse to vote" , "Formally decline to vote" , "Withhold one's vote" .)