insular vs island

insular is not a noun while island is a noun.

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

insular (noun)	island (noun)
	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water

insular (adjective)	island (adjective)
relating to or characteristic of or situated on an island
suggestive of the isolated life of an island
narrowly restricted in outlook or scope