Archaic term for a ghost or supernatural being. Not used in everyday modern Japanese; encountered mainly in classical literature or historical contexts.
古い怪談には、幽怪が夜な夜な現れる話が多い。
In old ghost stories, there are many tales of apparitions appearing night after night.
Compound of 幽 (dim, hidden, supernatural) and 怪 (mysterious, strange). The exact historical derivation is uncertain; it appears in classical texts as a term for ghosts or mysterious apparitions.