northern vs Yankee

northern is not a noun while Yankee is a noun.

Word	Noun	Adjective	Verb	Adverb
northern	No	Yes	No	No
Yankee	Yes	Yes	No	No

northern (noun)	Yankee (noun)
	an American (especially to non-Americans)
	an American who lives in New England
	an American who lives in the North (especially during the American Civil War)

northern (adjective)	Yankee (adjective)
situated in regions of the north	used by Southerners for an inhabitant of a northern state in the United States (especially a Union soldier)
in or characteristic of a region of the United States north of (approximately) the Mason-Dixon line
coming from the north; used especially of wind
oriented toward the north