Origin: (1) 1600-1700 From a Scandinavian language. (2) 1600-1700 loun bad person (15-19 centuries) (influenced by ➔ LOON(1) (because of its wild sound) and by ➔ LOONY1)
1a large North American bird that eats fish and that makes a long wild sound2a silly or strange person → see also crazy as a loonat crazy1 (8)