idiot

UK: /ˈɪdiət/ US: /ˈɪdiət/ ,(id′ē ət)

WordReference Random House Learner's Dictionary of American English © 2026

id•i•ot /ˈɪdiət/   n. [countable]

1. a completely stupid or foolish person:
   He was a total idiot to squander his life savings.
2. Psychology formerly, a person classified in the lowest rank of mental retardation.

WordReference Random House Unabridged Dictionary of American English © 2026

id•i•ot  (id′ē ət), n. 

1. an utterly foolish or senseless person.
2. Psychology a person of the lowest order in a former classification of mental retardation, having a mental age of less than three years old and an intelligence quotient under 25.

• Greek idió̄tēs private person, layman, person lacking skill or expertise, equivalent. to idiō- (lengthened variant of idio- idio-, perh. by analogy with stratiōtēs professional soldier, derivative of stratiá army) + -tēs agent noun, nominal suffix
• Latin idiōta
• Middle English 1250–1300

Synonyms

• 1. fool, half-wit; imbecile; dolt, dunce, numskull.

Collins Concise English Dictionary © HarperCollins Publishers::

idiot / ˈɪdɪət/ noun

1. a foolish or senseless person
2. a person with a severe learning disability

Etymology: 13th Century: from Latin idiōta ignorant person, from Greek idiōtēs private person, one who lacks professional knowledge, ignoramus; see idio-