island vs New Britain

island and New Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
island	Yes	No	No	No
New Britain	Yes	No	No	No

island (noun)	New Britain (noun)
a zone or area resembling an island	the largest island in the Bismarck Archipelago; part of Papua New Guinea
a land mass (smaller than a continent) that is surrounded by water