'Idiocy' definitions:

Definition of 'idiocy'

From: WordNet
noun
Extreme mental retardation [syn: idiocy, amentia]

Definition of 'Idiocy'

From: GCIDE
  • Idiocy \Id"i*o*cy\ ([i^]d"[i^]*[-o]*s[y^]), n. [From idiot; cf. Gr. ? uncouthness, lack of education, fr. ?. See Idiot, and cf. Idiotcy.] The condition or quality of being an idiot; absence, or marked deficiency, of sense and intelligence. [1913 Webster]
  • I will undertake to convict a man of idiocy, if he can not see the proof that three angles of a triangle are equal to two right angles. --F. W. Robertson. [1913 Webster]

Synonyms of 'idiocy'

From: Moby Thesaurus