showgirl vs dancer

showgirl and dancer both are nouns.

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

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

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

showgirl (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)