Idiocy \Id"i*o*cy\, n. [From idiot; cf. Gr. ? uncouthness, want of education, fr. ?. See Idiot, and cf. Idiotcy.]

The condition or quality of being an idiot; absence, or marked deficiency, of sense and intelligence.

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.

Source: Webster's Revised Unabridged Dictionary (1913)