Singapore vs island

Singapore and island both are nouns.

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

Singapore (noun)	island (noun)
a country in southeastern Asia on the island of Singapore; achieved independence from Malaysia in 1965	a zone or area resembling an island
an island to the south of the Malay Peninsula	a land mass (smaller than a continent) that is surrounded by water
the capital of Singapore; one of the world's biggest ports