American spelling vs extemporize

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

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

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

American spelling (verb)	extemporize (verb)
	perform without preparation
	manage in a makeshift way; do with whatever is at hand