chorus girl vs dancer

chorus girl and dancer both are nouns.

Word	Noun	Adjective	Verb	Adverb
chorus girl	Yes	No	No	No
dancer	Yes	No	No	No

As nouns, dancer is a hypernym of chorus girl; that is, dancer is a word with a broader meaning than chorus girl:

Other hypernyms of chorus girl include professional dancer, terpsichorean, adult female, woman.

chorus girl (noun)	dancer (noun)
a woman who dances in a chorus line	a performer who dances professionally
	a person who participates in a social gathering arranged for dancing (as a ball)