LETHAL meaning: 1. able to cause or causing death; extremely dangerous: 2. able to cause or causing death…. Learn more. Definition of lethal in the Definitions.net dictionary. Meaning of lethal. What does lethal mean? Information and translations of lethal in the most comprehensive dictionary definitions resource on the web. Synonyms for LETHAL: deadly, fatal, poisonous, infectious, infective, killer, harmful, toxic; Antonyms of LETHAL: healthy, nonlethal, beneficial, healthful, nonfatal. The meaning of LETHAL is of, relating to, or causing death. How to use lethal in a sentence. Synonym Discussion of Lethal. LETHAL definition: 1. able to cause or causing death; extremely dangerous: 2. able to cause or causing death…. Learn more. 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. LETHAL definition: of, relating to, or causing death; deadly; fatal: a lethal dose. See examples of lethal used in a sentence. LETHAL.GG is a leading enthusiast-focused retailer for high performance gaming mice, mousepads, keyboards, and accessories, serving players worldwide from its base in Alpharetta, GA since 2019. 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.