western vs western United States

western and western United States both are nouns.

Word	Noun	Adjective	Verb	Adverb
western	Yes	Yes	No	No
western United States	Yes	No	No	No

western (noun)	western United States (noun)
a sandwich made from a western omelet	the region of the United States lying to the west of the Mississippi River

western (adjective)	western United States (adjective)
relating to or characteristic of the western parts of the world or the West as opposed to the eastern or oriental parts
of or characteristic of regions of the United States west of the Mississippi River
lying toward or situated in the west
of wind; from the west