Mariana Islands vs GU

Mariana Islands and GU both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mariana Islands	Yes	No	No	No
GU	Yes	Yes	No	No

Mariana Islands (noun)	GU (noun)
a chain of coral and volcanic islands in Micronesia (including Guam and the Northern Marianas) halfway between New Guinea and Japan; discovered by Magellan in 1521	the largest and southernmost island in the Marianas which is administered as a territory of the United States; it was ceded by Spain to the United States in 1898

Mariana Islands (adjective)	GU (adjective)
	of or related to the genital and urinary organs or their functions