decolourise vs Australian spelling

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

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

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

decolourise (verb)	Australian spelling (verb)
cause to become white or lighter in color