showgirl vs adult female

showgirl and adult female both are nouns.

Word	Noun	Adjective	Verb	Adverb
showgirl	Yes	No	No	No
adult female	Yes	No	No	No

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

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

showgirl (noun)	adult female (noun)
a woman who dances in a chorus line	an adult female person (as opposed to a man)