An idiot, dolt, or dullard is a mentally deficient person, or someone who acts in a self-defeating or significantly counterproductive way. Archaically the word mome has also been used. The synonymous terms moron, imbecile, and cretin have all 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/an ignorant), neither of which refers to someone with low intelligence.