housemother vs adult female

housemother and adult female both are nouns.

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

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

Other hypernyms of housemother include chaperon, chaperone, woman.

housemother (noun)	adult female (noun)
a woman employed as a chaperon in a residence for young people	an adult female person (as opposed to a man)