metropolis vs Mosul

metropolis and Mosul both are nouns.

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

metropolis (noun)	Mosul (noun)
people living in a large densely populated municipality	a city in northern Iraq on the Tigris across from the ruins of Nineveh
a large and densely populated urban area; may include several independent administrative districts