GU vs genitourinary

GU is a noun but genitourinary is not a noun.

Word	Noun	Adjective	Verb	Adverb
GU	Yes	Yes	No	No
genitourinary	No	Yes	No	No

As adjectives, GU and genitourinary are synonyms defined as:

GU and genitourinary: of or related to the genital and urinary organs or their functions

GU (noun)	genitourinary (noun)
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

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