noun
imbecility; idiocy
A formal or clinical term for severe intellectual disability or foolishness. In modern usage, it is rare and may be considered outdated or offensive; more common terms include 知的障害 or 愚かさ.
彼は痴愚と見なされるような行動をとった。
He behaved in a way that could be regarded as imbecilic.
Composed of 痴 (foolish, stupid) and 愚 (foolish, ignorant). The exact historical derivation is uncertain, but the kanji combination directly conveys the meaning of severe foolishness or mental deficiency.