"Fantasy" (noun/adjective) is like a dream. It is something that isn't real (yet). "Going to Disneyland is like stepping into a fantasy world." "I want to have an easy job with a good salary. But maybe that's just a fantasy..." "Fancy" (adjective only) is like high-class. It can describe something usually expensive, like clothing or a party. "Wow! Your wedding dress is so fancy! Where did you buy it?" "That event is too fancy for someone like me! I don't even like wearing a suit!" Hope that helps!