From Wikipedia; The word "idiot" comes from the Greek ἰδιώτης, idiōtēs 'a private person, individual', 'a private citizen' (as opposed to an official), 'a common man', 'a person lacking professional skill, layman', later 'unskilled', 'ignorant' from ἴδιος, idios 'private', 'one's own'.[2] In Latin, idiota was borrowed in the meaning 'uneducated', 'ignorant', 'common',[3] and in Late Latin came to mean 'crude, illiterate, ignorant'.[4] In French, it kept the meaning of 'illiterate', 'ignorant', and added the meaning 'stupid' in the 13th century.