mystery; strangeness; bizarre phenomenon
Refers to something eerie, inexplicable, or uncanny; can be used as a noun or adjectivally with な. Often appears in literary or descriptive contexts.
その村では怪異な出来事が続いた。
Strange events continued in that village.
Concrete supernatural being: ghost, specter, goblin, or monstrous entity. Used in folklore, horror, and fantasy contexts.
He is fascinated by the world of the mysterious.
They say a ghost appears in the old mansion.
この絵巻には様々な怪異が描かれている。
Various monsters are depicted in this picture scroll.
怪異 and 怪奇 both describe eerie, supernatural strangeness, but 怪異 is more often used as a noun for a supernatural phenomenon itself, while 怪奇 is the descriptive adjective.
Compound of 怪 (kai, 'strange, mysterious') and 異 (i, 'unusual, different'). The exact historical derivation is uncertain, but the combination has been used since classical times to denote the eerie and supernatural.