idiotism

plural idiotisms

1. countablehistoricaluncountableVery severe mental retardation.

   He did not perceive that regal power, in a few generations, introduces idiotism into the noble stem […]

   1791 (date written), Mary Wollstonecraft, A Vindication of the Rights of Woman: With Strictures on Political and Moral Subjects, London: […] J[oseph] Johnson, […], published 1792, →OCLC

   1 more example

   Idiotism had long been accepted as hopeless: ‘Absolute idiocy admits of no cure,’ noted the nineteenth-century psychiatrist George Man Burrows (1771–1846).

   1997, Roy Porter, The Greatest Benefit to Mankind, Folio Society, published 2016, page 488

2. countableuncountableA foolish utterance.

   […] that clear soprano, in nursery, rings out a shower of innocent idiotisms over the half-stripped baby, and suspends the bawl upon its lips.

   1863, Sheridan Le Fanu, The House by the Churchyard

plural idiotisms

1. Idiom.
2. An overly literal translation of an idiom.