voter vs citizen

voter and citizen both are nouns.

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

As nouns, citizen is a hypernym of voter; that is, citizen is a word with a broader meaning than voter:

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

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