One of the electorate (5)
I believe the answer is:
voter
'one of the electorate' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for voter that I've seen before include "who may make one cross" , "One participating in ballot" , "Overt (anag)" , "One of the selectors" , "One exercising the ballot" .)