idiotismn.

Etymology: < (i) Middle French, French idiotisme stupidity (probably 1558: see note), linguistic peculiarity, peculiarity of speech (probably 1611: see note), and its etymon (ii) classical Latin idiōtismos everyday or homely speech, in post-classical Latin (as idiotismus) also simplicity, stupidity (4th cent.) < ancient Greek ἰδιωτισμός way or manner of a common person, homely or vulgar phrase < medieval Greek ἰδιωτίζειν (though this is apparently first attested later: see idiotize v.) + -ισμός -ism suffix. In branch II. perhaps also partly (iii) < idiot n. + -ism suffix. Compare Spanish idiotismo (1580 in sense ‘linguistic peculiarity’, 1635 or earlier in sense ‘nonsensical utterance’, 1648 or earlier in sense ‘idiocy, stupidity’), Italian idiotismo (1573 in sense ‘linguistic peculiarity’, 1869 in sense ‘idiocy, stupidity’). With the uses in branch I. compare slightly earlier idiom n.; with the uses in branch II. compare earlier idiocy n., idiotacy n., idiotry n.Middle French, French idiotisme is first attested in 1558 in a short story about the three fools Caillette, Triboulet, and Polite; the occurrence is as follows: Quand on disoit: ‘Ce ont esté les pages?’, Caillette respondoit bien en son idiotisme: ‘Ouy, ouy, ce ont esté les pages’. Given the wider context of the instance, and the fact that while Caillette's utterance is not recognizably regional or idiolectal, he clearly answers in a mechanical way, the quotation is much more likely to show the sense ‘stupidity’ (which is subsequently attested e.g. in 1595, as well as in Cotgrave 1611) than the linguistic sense ‘peculiarity of speech’, even though all authoritative dictionaries of French regard the quot. as showing the latter sense. The linguistic sense ‘peculiarity of speech (especially on the syntactic or phraseological level)’ is not securely attested before 1611 (in Cotgrave); although the sense ‘idiocy, stupidity’ is influenced by Middle French, French idiot idiot n., both senses can be derived from the same Latin etymon without problems.