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. LETHAL definition: 1. able to cause or causing death; extremely dangerous: 2. able to cause or causing death…. Learn more. A co-op horror about scavenging at abandoned moons to sell scrap to the Company. LETHAL definition: of, relating to, or causing death; deadly; fatal: a lethal dose. See examples of lethal used in a sentence. Define lethal. lethal synonyms, lethal pronunciation, lethal translation, English dictionary definition of lethal. adj. 1. Causing or capable of causing death: a lethal weapon. See Synonyms at fatal. 2. Extremely harmful; devastating: accusations lethal to the. Synonyms for LETHAL: deadly, fatal, poisonous, infectious, infective, killer, harmful, toxic; Antonyms of LETHAL: healthy, nonlethal, beneficial, healthful, nonfatal. lethal (comparative more lethal, superlative most lethal) Of, pertaining to, or causing death; deadly; mortal; fatal. LETHAL meaning: 1. able to cause or causing death; extremely dangerous: 2. able to cause or causing death…. Learn more. At LETHAL Corporation it is our objective to bring people back to the forefront of why they possess arms – why they should train regularly – why they should carry weapons every day – and why lethality, in certain life-threatening situations, is the capability to be desired rather than vilified. The meaning of LETHAL is of, relating to, or causing death. How to use lethal in a sentence. Synonym Discussion of Lethal.