freshman vs U.S.

freshman and U.S. both are nouns.

Word	Noun	Adjective	Verb	Adverb
freshman	Yes	Yes	No	No
U.S.	Yes	No	No	No

freshman (noun)	U.S. (noun)
a first-year undergraduate	the executive and legislative and judicial branches of the federal government of the United States
any new participant in some activity	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

freshman (adjective)	U.S. (adjective)
used of a person in the first year of an experience (especially in United States high school or college)