Word Study 1.fantasize n.to imagine that you are doing sth which is very pleasant or exciting,but which is very unlikely to happen Sometimes she fantasized about buying a boat and sailing around the world. I used to fantasize that my real parents were famous movie stars. fantasy (n.) fantastic (a. 1. fantasize n. to imagine that you are doing sth which is very pleasant or exciting, but which is very unlikely to happen Sometimes she fantasized about buying a boat and sailing around the world. I used to fantasize that my real parents were famous movie stars. Word Study fantasy (n.) fantastic (a.)