Abderian (ab-DE-ri-en) Adjective: -Of or belonging to the ancient city of Abdera or to its inhabitants. -Given to incessant or idiotic laughter. From Abdera, city of ancient Thrace (borrowed from Greek Ábdera) + -ian. First Known Use: 1737 Used in a sentence: "It occurs to me that your rather abderian persona is working against you as a salesman. It smacks of insincerity to potential customers."