Black man vs Black

Black man and Black both are nouns.

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

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

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

Other hypernyms of Black man include African-American, Negro, Negroid, adult male, man, Black person, blackamoor.

Black man (noun)	Black (noun)
a man 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)