freshman vs USA

freshman and USA both are nouns.

Word	Noun	Adjective	Verb	Adverb
freshman	Yes	Yes	No	No
USA	Yes	No	No	No

freshman (noun)	USA (noun)
a first-year undergraduate	the army of the United States of America; the agency that organizes and trains soldiers for land warfare
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)	USA (adjective)
used of a person in the first year of an experience (especially in United States high school or college)