Yea or nay, say (4)
I believe the answer is:
vote
This clue is a double definition.
'yea or nay' is the first definition.
(I've seen this in another clue)
'say' is the second definition.
(thesaurus)
(Other definitions for vote that I've seen before include "Mark on ballot paper" , "Poll" , "What suffragettes wanted" , "Participate in an election" , "Put one's cross" .)