island vs Antigua

island and Antigua both are nouns.

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

island (noun)	Antigua (noun)
a zone or area resembling an island	the largest of the islands comprising Antigua and Barbuda
a land mass (smaller than a continent) that is surrounded by water