Zimbabwean vs African

Zimbabwean and African both are nouns.

Word	Noun	Adjective	Verb	Adverb
Zimbabwean	Yes	Yes	No	No
African	Yes	Yes	No	No

As nouns, African is a hypernym of Zimbabwean; that is, African is a word with a broader meaning than Zimbabwean:

Zimbabwean (noun)	African (noun)
a native or inhabitant of Zimbabwe	a native or inhabitant of Africa

Zimbabwean (adjective)	African (adjective)
of or relating to or characteristic of Zimbabwe or its people	of or relating to the nations of Africa or their peoples