I.destructive, pernicious, deadly (rare but class.): “conjuratio,” Cic. Cat. 4, 3, 6: “quibus a servis caedem fieri senatus et bonorum rei publicae exitiosum fuisset,” id. Planc. 36, 87; cf.: “quod exitiosum fore, si evenisset, videbam,” id. Fam. 6, 1, 5.—Of persons (post-Aug.): “rex,” Tac. A. 6, 36; id. H. 1, 68.—Comp.: “Otho luxu, saevitia, audacia reipublicae exitiosior ducebatur,” Tac. H. 2, 31.—Sup., Tert. Anim. 34.—Adv.: ex-ĭtĭōsē , perniciously.—Sup., Aug. Ep. 8, 3.
exĭtĭōsus , a, um, adj. exitium,