Nauru Island vs Nauru

Nauru Island and Nauru both are nouns.

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

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

Nauru Island and Nauru: a small island in the central Pacific Ocean 2,800 miles to the southwest of Hawaii; in Micronesia to the west of the Gilbert Islands

Other synonyms of Nauru Island include Pleasant Island.

Nauru Island (noun)	Nauru (noun)
a small island in the central Pacific Ocean 2,800 miles to the southwest of Hawaii; in Micronesia to the west of the Gilbert Islands	an island republic on Nauru Island; phosphate exports support the economy
	a small island in the central Pacific Ocean 2,800 miles to the southwest of Hawaii; in Micronesia to the west of the Gilbert Islands