saleswoman vs adult female

saleswoman and adult female both are nouns.

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

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

Other hypernyms of saleswoman include sales rep, sales representative, salesperson, woman.

saleswoman (noun)	adult female (noun)
a woman salesperson	an adult female person (as opposed to a man)