western United States vs western

western United States and western both are nouns.

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

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

western United States (adjective)	western (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