<p><strong>Noun:</strong></p><ul><li>Informal. A dunce; blockhead; dolt: Don't stand there like an imbecile. Open the door!</li><li>Psychology. (no longer in technical use; now considered offensive) A person of the second order in a former and discarded classification of intellectual disability, above the level of idiocy, having a mental age of seven or eight years and an intelligence quotient of 25 to 50.</li></ul><p><strong>Adjective:</strong></p><ul><li>Informal. Stupid; silly; absurd.</li><li>Usually Offensive. Showing mental feebleness or incapacity.</li><li>Archaic. Weak or feeble.</li></ul>