American spelling vs unappetizing

American spelling is a noun but unappetizing is not a noun.

Word	Noun	Adjective	Verb	Adverb
American spelling	Yes	No	No	No
unappetizing	No	Yes	No	No

American spelling (noun)	unappetizing (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')

American spelling (adjective)	unappetizing (adjective)
	not appetizing in appearance, aroma, or taste