Rawalpindi vs metropolis

Rawalpindi and metropolis both are nouns.

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

Rawalpindi (noun)	metropolis (noun)
an ancient city in northeastern Pakistan; served as capital of Pakistan while Islamabad was being built	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts