fantasy vs fantasise

fantasy is a noun but fantasise is not a noun.

Word	Noun	Adjective	Verb	Adverb
fantasy	Yes	No	Yes	No
fantasise	No	No	Yes	No

As verbs, fantasy and fantasise are synonyms defined as:

Other synonyms of fantasy include fantasize.

fantasy (noun)	fantasise (noun)
imagination unrestricted by reality
something many people believe that is false
fiction with a large amount of imagination in it

fantasy (verb)	fantasise (verb)
indulge in fantasies	indulge in fantasies
	portray in the mind