Bombay vs metropolis

Bombay and metropolis both are nouns.

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

Bombay (noun)	metropolis (noun)
a city in western India just off the coast of the Arabian Sea; India's 2nd largest city (after Calcutta); has the only natural deep-water harbor in western India	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts