noun
evil spirit; vengeful ghost; specter
Refers to a malevolent supernatural being in Japanese folklore, often a spirit that possesses or curses people. Strongly associated with traditional tales and the Ghibli film 'Princess Mononoke'.
この森には物の怪が住んでいると言われている。
It is said that evil spirits live in this forest.
彼は物の怪に取り憑かれたように様
He is acting strange, as if possessed by a vengeful ghost.
Rarely used kanji form; 気 can suggest a spirit or energy, but this spelling is uncommon.
妖怪 is a broader term for all kinds of Japanese monsters and supernatural creatures, while 物の怪 specifically implies a malevolent or vengeful spirit.
幽霊 is a general term for ghosts of the dead, often depicted as white-clad figures; 物の怪 carries a stronger sense of active malice and supernatural power.
Compound of 物 (mono, 'thing') + の (no, possessive particle) + 怪 (ke, 'mysterious, strange'). The reading け is an older form of 怪, and the word originally referred to a mysterious or strange phenomenon, later personified as a malevolent spirit.