An idiot, dolt, dullard or (archaically) mome is a person perceived to be lacking intelligence, or someone who acts in a self-defeating or significantly counterproductive way. Along with the similar terms moron, imbecile, and cretin, the word archaically referred to the intellectually disabled, but have all since gained specialized meanings in modern times. An idiot is said to be idiotic, and to suffer from idiocy.
A dunce is an idiot who is specifically incapable of learning. An idiot differs from a fool (who is unwise) and an ignoramus (who is uneducated/ignorant), neither of which refers to someone with low intelligence. In modern English usage, the terms "idiot" and "idiocy" describe an extreme folly or stupidity, and its symptoms (foolish or stupid utterance or deed). In psychology, it is a historical term for the state or condition now called profound intellectual disability.