city vs Karachi

city and Karachi both are nouns.

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

city (noun)	Karachi (noun)
people living in a large densely populated municipality	the largest city in Pakistan; located in southeastern Pakistan; an industrial center and seaport on the Arabian Sea; former capital of Pakistan
a large and densely populated urban area; may include several independent administrative districts
an incorporated administrative district established by state charter