darky vs Negro

darky and Negro both are nouns.

Word	Noun	Adjective	Verb	Adverb
darky	Yes	No	No	No
Negro	Yes	No	No	No

As nouns, Negro is a hypernym of darky; that is, Negro is a word with a broader meaning than darky:

darky: (ethnic slur) offensive term for Black people
Negro: a person with African ancestry, "Negro" and "Negroid" are archaic and pejorative today

Other hypernyms of darky include African-American, Black, Negroid, Black person, blackamoor.

darky (noun)	Negro (noun)
(ethnic slur) offensive term for Black people	a person with African ancestry, "Negro" and "Negroid" are archaic and pejorative today