British spelling vs agonise

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

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

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

British spelling (verb)	agonise (verb)
	suffer agony or anguish
	cause to agonize