murderess vs adult female

murderess and adult female both are nouns.

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

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

Other hypernyms of murderess include liquidator, manslayer, murderer, woman.

murderess (noun)	adult female (noun)
a woman murderer	an adult female person (as opposed to a man)