noun
demoness; ogress; she-devil
Mythological or folkloric female demon, often depicted as a fierce, monstrous woman. Can also be used figuratively for a cruel or terrifying woman.
昔話に出てくる鬼女は、山奥に住んでいた。
The demoness in the old tale lived deep in the mountains.
彼女は怒ると鬼女のように怖い。
When she gets angry, she's as scary as a demoness.
noun
married woman (slang, derogatory or jocular)
Internet slang pun on 既女 (also read きじょ, 'already a woman'), used derogatorily or jokingly to refer to a married woman, often implying she is no longer desirable or has a fierce personality. Not used in polite conversation.
See also: 既女
ネットでは、既婚女性を「鬼女」と呼ぶことがある。
On the internet, married women are sometimes called 'demonesses' (a pun on 既女).
Compound of 鬼 (oni, 'demon') and 女 (onna, 'woman'). The slang sense is a pun on the homophone 既女 (kijo, 'already a woman').