dancer vs waltzer

dancer and waltzer both are nouns.

Word	Noun	Adjective	Verb	Adverb
dancer	Yes	No	No	No
waltzer	Yes	No	No	No

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

dancer: a person who participates in a social gathering arranged for dancing (as a ball)
waltzer: a dancer who waltzes

Other hyponyms of dancer include clog dancer, dancing partner, folk dancer, raver.

dancer (noun)	waltzer (noun)
a performer who dances professionally	a dancer who waltzes
a person who participates in a social gathering arranged for dancing (as a ball)