Idiot

'Idiot' was formerly a technical term in legal and psychiatric contexts for some kinds of profound intellectual disability where the mental age is two years or less, and the person cannot guard themself against common physical dangers.

Thucydides quotes Pericles' Funeral Oration as saying: "[we] regard... him who takes no part in these [public] duties not as unambitious but as useless" (Ancient Greek: τόν τε μηδὲν τῶνδε μετέχοντα οὐκ ἀπράγμονα, ἀλλ᾽ ἀχρεῖον νομίζομεν).

[9] However, neither he nor any other ancient author uses the word "idiot" to describe non-participants, or in a derogatory sense; its most common use was simply a private citizen or amateur as opposed to a government official, professional, or expert.

In the early 1900s, Dr. Henry H. Goddard proposed a classification system for intellectual disability based on the Binet-Simon concept of mental age.

The most common intersection between these two categories of mental impairment occurs in the polemic surrounding Edmund from William Shakespeare's King Lear.

In Fyodor Dostoevsky's novel The Idiot the title refers to the central character Prince Myshkin, a man whose innocence, kindness and humility, combined with his occasional epileptic symptoms, cause many in the corrupt, egoistic culture around him to mistakenly assume that he lacks intelligence.