n.
 (pl. fantasies)
   - the faculty or activity of imagining improbable things. 
▸a pleasant or desirable imaginary situation:
 the notion of being independent is a child's ultimate fantasy.
  ▸an idea with no basis in reality.
 - a genre of imaginative fiction involving magic and adventure.
 - a fantasia.
 
v.
 (fantasies, fantasying, fantasied)
 literary fantasize about.
 
  Etymology
  ME: from OFr. fantasie, from L. phantasia, from Gk ‘imagination, appearance’, later ‘phantom’, from phantazein (see fantastic).