Nauseous \Nau"seous\ (?; 277), a. [L. nauseosus.] Causing, or fitted to cause, nausea; sickening; loathsome; disgusting; exciting abhorrence; as, a nauseous drug or medicine. -- {Nau"seous*ly}, adv. -- {Nau"seous*ness}, n. The nauseousness of such company disgusts a reasonable man. --Dryden.