What is the Latin word for deadly?

The usual Latin words for “deadly” are mortifer, exitiālis, capitālis; also lētifer, inimīcus, hostis. The right choice depends on the sense; see the distinctions below.

English → Latin

“deadly” in Latin

mortiferdeadly, fatal, lethal exitiālisdestructive; fatal, deadly capitālisof the head or life; dangerous, which concerns the life or death; deadly, mortal lētiferdeadly, fatal; death-dealing inimīcusenemy, foe (someone who is hostile to, feels hatred towards, opposes the interests of, or intends injury to someone else hostisan enemy of the state, an enemy, a hostile, opponent, foe; the enemy adversāriusadverse, hostile implācābilisunappeasable, implacable; irreconcilable inexpiābilisimplacable; inexpiable cadāverōsuscorpse-like

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

deadly adj.

mortifer (death-bringing; e.g., a cut, thrust, wound, sickness: ☞ not to be used figuratively, poetical letalis or letifer): exitialis (bringing ruin and destruction): capitalis (even to death): a deadly enemy, inimicus (hostis, adversarius) capitalis: to show one’s self anybody’s deadly enemy, se alicui implacabilem inexpiabilemque praebere. A deadly hatred, odium capitale, or implacabile, or inexpiabile (☞ not odium mortiferum): a deadly feud, inimicitiae gravissimae: to harbour a deadly hatred against anybody, capitali odio a aliquo dissidere; implacabile odium in aliquem suscepisse: a deadly poison, venenum dirum, malum or exitiale (after Plin., ; animalia venenata magis exitialia, si, etc.): (a cup of) deadly poison, poculum mortis: deadly sin, (grande) nefas: to think it a deadly sin to, etc., nefas habere or credere (with infinitive).

deadly adv.

mortifere: to fall deadly wounded, mortifero vulnere ictum cadere. Deadly pale, cadaverosus: laridus (in a bad sense): perpallidus: exsanguis.

Quick answer

What is the Latin word for deadly?: The usual Latin words for “deadly” are mortifer, exitiālis, capitālis; also lētifer, inimīcus, hostis. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.