ambassadress vs ambassador

ambassadress and ambassador both are nouns.

Word	Noun	Adjective	Verb	Adverb
ambassadress	Yes	No	No	No
ambassador	Yes	No	No	No

As nouns, ambassador is a hypernym of ambassadress; that is, ambassador is a word with a broader meaning than ambassadress:

ambassadress: a woman ambassador
ambassador: a diplomat of the highest rank; accredited as representative from one country to another

Other hypernyms of ambassadress include embassador, adult female, woman.

ambassadress (noun)	ambassador (noun)
a woman ambassador	a diplomat of the highest rank; accredited as representative from one country to another
	an informal representative