The Chinese word 妖怪 (yāoguài), meaning "monster" or "demon", is a compound term formed by combining two semantically related characters: 妖 (yāo), which conveys a sense of the supernatural, bewitching, or eerie, often with a malicious or aberrant nature, and 怪 (guài), which means "strange", "uncanny", or "monstrous". Together, they create a synergistic meaning that emphasizes a being or entity that is both supernaturally aberrant and strangely monstrous, perfectly encapsulating the concept of a mythical creature or hostile spirit in Chinese folklore and mythology.