verb (used without object), fan·ta·sized, fan·ta·siz·ing.
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), fan·ta·sized, fan·ta·siz·ing.
to create in one's fancy, daydreams, or the like; imagine: to fantasize a trip through space.
Also especially British, fan·ta·sise.
Origin of fantasize
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(when tr, takes a clause as object) to conceive extravagant or whimsical ideas, images, etc
(intr) to conceive pleasant or satisfying mental images
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Online Etymology Dictionary, © 2010 Douglas Harper