alumnus vs adult female

alumnus and adult female both are nouns.

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

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

alumnus: a male person who has received a degree from a school (high school or college or university)
adult female: an adult female person (as opposed to a man)

Other hypernyms of alumnus include alum, grad, graduate, woman.

alumnus (noun)	adult female (noun)
a male person who has received a degree from a school (high school or college or university)	an adult female person (as opposed to a man)