verb (used without object), fantasized, fantasizing.
to conceive fanciful or extravagant notions, ideas, suppositions, or the like (often followed by about
): to fantasize about the ideal job.
verb (used with object), fantasized, fantasizing.
to create in one's fancy, daydreams, or the like; imagine: to fantasize a trip through space.
Also, especially British, fantasise.