LETHAL definition: of, relating to, or causing death; deadly; fatal: a lethal dose. See examples of lethal used in a sentence. 1. Causing or capable of causing death: a lethal weapon. See Synonyms at fatal. 2. Extremely harmful; devastating: accusations lethal to the candidate's image. Byrna Less-Lethal pistols are non lethal self defense weapons powered by compressed air (CO2) and fire chemical and / or kinetic rounds capable of incapacitating a threatening suspect from up to 60ft feet away for up to 45 minutes. Explore the wondrous outdoors and rummage through their derelict, steel and concrete underbellies. Just never miss the quota. These dangers prey upon the vulnerable and lonesome, and the protection of your crew may be your only hope. A substance that is lethal can kill people or animals.a lethal dose of sleeping pills.chemicals lethal to fish and aquatic mammals. Lethal refers to anything dangerous enough to cause death. The cobra's venom is so lethal that if you get bitten and can't find the antidote, it's lights out forever. Poisonous spiders, guns, knives, and radiation — all of these things can be lethal because they have the ability to kill. Lethal definition: Causing or capable of causing death. Add to word list able to cause or causing death; extremely dangerous: a lethal weapon (Definition of lethal from the Cambridge Academic Content Dictionary © Cambridge University Press) lethal applies to something that is bound to cause death or exists for the destruction of life. Learn what lethal means with clear definitions, pronunciation, synonyms, and real-world examples. Simple explanations to help you use lethal correctly.