n.1 colloq. a stupid person; an utter fool.
2 a person deficient in mind and permanently incapable of rational conduct.
Phrases and idioms:
idiot board (or card) colloq. a board displaying a television script to a speaker as an aid to memory.
Derivatives:
idiotic adj. idiotically adv.
Etymology: ME f. OF f. L idiota ignorant person f. Gk idiotes private person, layman, ignorant person f. idios own, private