(adj.adv.) : mortĭferor (rarely) mortĭfĕrus, ĕra, ĕrum, adj. mors-fero
* Death-bringing, death-dealing, deadly, fatal (class.; syn.: lethalis, funestus): poculum,Cic. Tusc. 1, 29, 71: morbus,id. Div. 1, 30, 63: vulnus,id. Leg. 2, 5, 13: bellum,Verg. A. 6, 279: gravior dolor nec tamen mortiferus,Cels. 4, 2 init.; 5, 26, 22; Aug. de Util. Cred. § 36: res mortifera est inimicus pumice levis,Juv. 9, 95; 10, 10.—Neutr. plur. as subst.: mortĭfĕra, um, deadly things: cur tam multa mortifera terra mortique (deus) disperserit,Cic. Ac. 2, 38, 120 (B. and K. pestifera).—Hence, adv.: mortĭfĕrē, mortally, fatally (post-Aug.): mortifere aegrotare,Plin. Ep. 3, 16, 3: vulnerare,Dig. 9, 2, 36, § 1.

s. TLL