American spelling vs subtilize

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

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

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

American spelling (verb)	subtilize (verb)
	make more subtle or refined
	make (senses) more keen
	mark fine distinctions and subtleties, as among words