Saint John vs city

Saint John and city both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint John	Yes	No	No	No
city	Yes	No	No	No

Saint John (noun)	city (noun)
a port in eastern Canada; the largest city in New Brunswick	people living in a large densely populated municipality
a river that rises in Maine and flows northeastward through New Brunswick to empty into the Bay of Fundy	a large and densely populated urban area; may include several independent administrative districts
(New Testament) disciple of Jesus; traditionally said to be the author of the 4th Gospel and three epistles and the book of Revelation	an incorporated administrative district established by state charter