St. Christopher vs island

St. Christopher and island both are nouns.

Word	Noun	Adjective	Verb	Adverb
St. Christopher	Yes	No	No	No
island	Yes	No	No	No

St. Christopher (noun)	island (noun)
the largest of the islands comprising Saint Christopher-Nevis	a zone or area resembling an island
Christian martyr and patron saint of travellers (3rd century)	a land mass (smaller than a continent) that is surrounded by water