The word 幻想 is formed by combining two characters: 幻, which means "illusion" or "unreal", and 想, which means "to think" or "imagine". The formation is purely semantic, where the first character defines the nature or quality (illusory) and the second character provides the action or process (thinking). Together, they conceptually merge to create a single meaning, "fantasy" or "daydream", which is essentially the act or product of illusory thinking.