Black woman vs Black

Black woman and Black both are nouns.

Word	Noun	Adjective	Verb	Adverb
Black woman	Yes	No	No	No
Black	Yes	No	No	No

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

Black woman: a woman who is Black
Black: a person with African ancestry, "Negro" and "Negroid" are archaic and pejorative today

Other hypernyms of Black woman include African-American, Negro, Negroid, adult female, woman, Black person, blackamoor.

Black woman (noun)	Black (noun)
a woman who is Black	a person with African ancestry, "Negro" and "Negroid" are archaic and pejorative today
	popular child actress of the 1930's (born in 1928)
	British chemist who identified carbon dioxide and who formulated the concepts of specific heat and latent heat (1728-1799)