1. any of a range of mental experiences and processes marked by vivid imagery, intensity of emotion, and relaxation or absence of logic. Fantasizing is normal and common and often serves a healthy purpose of releasing tension, giving pleasure and amusement, or stimulating creativity. It can also be indicative of pathology, as in delusional thinking or significant disconnection from reality.

2. in psychoanalytic theories, a figment of the imagination: a mental image, night dream, or daydream in which a person’s conscious or unconscious wishes and impulses are fulfilled (see wish fulfillment). Followers of Melanie Klein use the spelling phantasy to denote specifically unconscious wishes. —fantasize vb.