Lanai vs Lanai Island

Lanai and Lanai Island both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lanai	Yes	No	No	No
Lanai Island	Yes	No	No	No

As nouns, Lanai and Lanai Island are synonyms defined as:

Lanai and Lanai Island: an island of central Hawaii; a pineapple-growing area

Lanai (noun)	Lanai Island (noun)
an island of central Hawaii; a pineapple-growing area	an island of central Hawaii; a pineapple-growing area