Lewis Short
(adjective) : exĭtĭābĭlis, e, exitium
* Destructive, fatal, deadly (rare but class.): exitiabilem illi faciam diem,Plaut. Ep. 4, 2, 36: bellum suis civibus, * Cic. Att. 10, 4, 3; so, bellum,Eutr. 9, 7: tyrannus,Liv. 29, 17, 19: clades,Suet. Aug. 23: discordiae,id. Claud. 25: reipublicae,Tac. H. 2, 69: morbus,id. A. 16, 5: fames,Vell. 2, 112, 3: telum,Ov. M. 6, 257: animus in suos,Tac. A. 6, 24: superstitio,id. ib. 15, 44.—Adv.: exĭtĭā-bĭlĭter, perniciously, fatally, August. Civ. D. 1, 17.
Charlton T. Lewis, Charles Short, A Latin Dictionary