citizen vs voter

citizen and voter both are nouns.

Word	Noun	Adjective	Verb	Adverb
citizen	Yes	No	No	No
voter	Yes	No	No	No

As nouns, voter is a hyponym of citizen; that is, voter is a word with a more specific, narrower meaning than citizen:

citizen: a native or naturalized member of a state or other political community
voter: a citizen who has a legal right to vote

Other hyponyms of citizen include active citizen, civilian, freeperson, private citizen, repatriate, thane, elector.

citizen (noun)	voter (noun)
a native or naturalized member of a state or other political community	a citizen who has a legal right to vote