vestrywoman vs adult female

vestrywoman and adult female both are nouns.

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

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

Other hypernyms of vestrywoman include church officer, woman.

vestrywoman (noun)	adult female (noun)
a woman who is a member of a church vestry	an adult female person (as opposed to a man)