Elector (5)
I believe the answer is:
voter
'elector' is the definition.
(I know that elector can be written as voter)
This is the entire clue.
(Other definitions for voter that I've seen before include "One of the selectors" , "one making sign of the cross" , "One exercising the ballot" , "Overt (anag)" , "who may make one cross" .)