Nanjing vs city

Nanjing and city both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nanjing	Yes	No	No	No
city	Yes	No	No	No

Nanjing (noun)	city (noun)
a city in eastern China on the Yangtze River; a former capital of China; the scene of a Japanese massacre in the 1930s	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts
	an incorporated administrative district established by state charter