an utterly foolish or senseless person.

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.

noun

brain

noun

blockhead , bonehead * , cretin , dimwit , dork , dumbbell , dunce , fool , ignoramus , imbecile , jerk , kook * , moron , nincompoop , ninny , nitwit , out to lunch , pinhead * , simpleton , stupid , tomfool , twitnotes:an idiot is a stupid person with a mental age below three years , while a moron is a stupid person with a mental age of between seven to twelve years , ass , jackass , mooncalf , simple , softhead , ament , bonehead , booby , dolt , dope , dullard , fathead , twit