Douala vs metropolis

Douala and metropolis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Douala	Yes	No	No	No
metropolis	Yes	No	No	No

Douala (noun)	metropolis (noun)
the largest city of Cameroon	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts