U.S. vs Mel Columcille Gerard Gibson

U.S. and Mel Columcille Gerard Gibson both are nouns.

Word	Noun	Adjective	Verb	Adverb
U.S.	Yes	No	No	No
Mel Columcille Gerard Gibson	Yes	No	No	No

U.S. (noun)	Mel Columcille Gerard Gibson (noun)
the executive and legislative and judicial branches of the federal government of the United States	Australian actor (born in the United States in 1956)
North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776