idiotism

noun

1. (countable, historical, uncountable)Very severe mental retardation.

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

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

2. (countable, uncountable)A 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.”

3. Idiom.
4. An overly literal translation of an idiom.