British spelling vs unionise

British spelling is a noun but unionise is not a noun.

Word	Noun	Adjective	Verb	Adverb
British spelling	Yes	No	No	No
unionise	No	No	Yes	No

British spelling (noun)	unionise (noun)
English orthography used in the UK, Ireland and most of the Commonwealth (characterized by 'analyse', 'centre' and 'useable')

British spelling (verb)	unionise (verb)
	form or join a union
	recruit for a union or organize into a union