island vs Kauai

island and Kauai both are nouns.

Word	Noun	Adjective	Verb	Adverb
island	Yes	No	No	No
Kauai	Yes	No	No	No

island (noun)	Kauai (noun)
a zone or area resembling an island	an island of Hawaii to the northwest of Oahu
a land mass (smaller than a continent) that is surrounded by water