theorise vs Australian spelling

theorise is not a noun while Australian spelling is a noun.

Word	Noun	Adjective	Verb	Adverb
theorise	No	No	Yes	No
Australian spelling	Yes	No	No	No

theorise (noun)	Australian spelling (noun)
	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')

theorise (verb)	Australian spelling (verb)
to believe especially on uncertain or tentative grounds