Missouri vs midwestern United States

Missouri and midwestern United States both are nouns.

Word	Noun	Adjective	Verb	Adverb
Missouri	Yes	No	No	No
midwestern United States	Yes	No	No	No

Missouri (noun)	midwestern United States (noun)
a dialect of the Chiwere language spoken by the Missouri	the north central region of the United States (sometimes called the heartland or the breadbasket of America)
a midwestern state in central United States; a border state during the American Civil War, Missouri was admitted to the Confederacy without actually seceding from the Union
the longest river in the United States; arises in Montana and flows southeastward to become a tributary of the Mississippi at Saint Louis
a member of the Siouan people formerly inhabiting the valley of the Missouri river in Missouri