interfectōrĭus

I. deadly, murderous (late Lat.), Aug. de Lib. Arb. 3, 25; Isid. Orig. 17, 7, 7.— Subst.: interfectōrĭum, i, n., a means of destruction, Ambros. de Elia et Jejun. 10, 37 fin.—Hence, adv.: interfectōrĭē, destructively, murderously, Aug. contr. Parm. 3, 2, 14.