There are many synonyms for the word "fantasizer" or someone who indulges in fantasies. Some common alternatives include dreamer, ideator, daydreamer, visionary, and creator. Dreamer refers to someone who has a vivid imagination and often dreams big. Ideator refers to someone who is constantly coming up with new and innovative ideas. Daydreamer is a more casual term for someone who spends a lot of time imagining scenarios in their mind. Visionary is used to describe someone who has a strong sense of the future and a unique perspective on the world. Lastly, creator refers to someone who uses their imagination to make something that did not previously exist.