tranquillise vs British spelling

tranquillise is not a noun while British spelling is a noun.

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

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

tranquillise (verb)	British spelling (verb)
cause to be calm or quiet as by administering a sedative to
make calm or still