Black African vs caffer

Black African and caffer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Black African	Yes	No	No	No
caffer	Yes	No	No	No

As nouns, caffer is a hyponym of Black African; that is, caffer is a word with a more specific, narrower meaning than Black African:

Other hyponyms of Black African include caffre, kaffir, kafir.

Black African (noun)	caffer (noun)
an African who is Black	an offensive and insulting term for any Black African