island vs Viti Levu

island and Viti Levu both are nouns.

Word	Noun	Adjective	Verb	Adverb
island	Yes	No	No	No
Viti Levu	Yes	No	No	No

island (noun)	Viti Levu (noun)
a zone or area resembling an island	a volcanic island in the Fijis, the largest island in Fiji
a land mass (smaller than a continent) that is surrounded by water