Negress vs Black person

Negress and Black person both are nouns.

Word	Noun	Adjective	Verb	Adverb
Negress	Yes	No	No	No
Black person	Yes	No	No	No

As nouns, Black person is a hypernym of Negress; that is, Black person is a word with a broader meaning than Negress:

Negress: a Black woman or girl
Black person: a person with dark skin who comes from Africa (or whose ancestors came from Africa)

Other hypernyms of Negress include African-American, Black, Negro, Negroid, blackamoor.

Negress (noun)	Black person (noun)
a Black woman or girl	a person with dark skin who comes from Africa (or whose ancestors came from Africa)