nursemaid vs adult female

nursemaid and adult female both are nouns.

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

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

Other hypernyms of nursemaid include keeper, woman.

nursemaid (noun)	adult female (noun)
a woman who is the custodian of children	an adult female person (as opposed to a man)