Ho Chi Minh City vs metropolis

Ho Chi Minh City and metropolis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ho Chi Minh City	Yes	No	No	No
metropolis	Yes	No	No	No

Ho Chi Minh City (noun)	metropolis (noun)
a city in South Vietnam; formerly (as Saigon) it was the capital of French Indochina	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts