British spelling vs euthanise

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

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

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

British spelling (verb)	euthanise (verb)
	intentionally cause the painless death of a person or animal