British spelling vs tranquillise

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

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

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

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