Entry 1 sense Webster, 1913 Thwarter · Thwart·er · IPA /ˈθwɔː(ɹ).tə(ɹ)/ 01 n. A disease in sheep, indicated by shaking, trembling, or convulsive motions. 1. A disease in sheep, indicated by shaking, trembling, or convulsive motions.(Far.)