missy vs adult female

missy and adult female both are nouns.

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

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

Other hypernyms of missy include woman.

missy (noun)	adult female (noun)
a young female	an adult female person (as opposed to a man)