lethal
Americanadjective
-
able to cause or causing death
-
of or suggestive of death
Synonym Usage
See fatal.
Other Word Forms
Etymology
Origin of lethal
First recorded in 1575–85; from Latin lētālis, equivalent to lēt(um) “death” + -ālis -al 1; spelling (hence pronunciation) with -h- by association with Greek lḗthē “oblivion”; see Lethe ( def. )
Explanation
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. Even some substances that on their own aren't dangerous can become lethal in large quantities. Eating a peanut butter sandwich won't hurt most people, but it can be lethal to those with a nut allergy. Words like deadly and fatal have meanings that are similar to lethal.
Vocabulary lists containing lethal
100 SAT Words Beginning with "J," "K," and "L"
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A Long Way Gone
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Silent Spring
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
While the cane toad is not a direct threat to Rio Tinto's business, it produces toxins lethal to native wildlife and poses a threat to Pilbara's ecosystem.
From BBC ● Nov. 3, 2026
Pike is the only inmate to ever survive after being injected with lethal doses of execution drugs, according to the Death Penalty Information Center.
From Barron's ● Oct. 30, 2026
When Gladwell investigates whether those features actually make a gun more lethal, the case largely falls apart.
From Los Angeles Times ● Oct. 27, 2026
Glioblastoma is among the most lethal forms of brain cancer, and scientists have uncovered a surprising factor that may help its cells become more invasive.
From Science Daily ● Oct. 24, 2026
He was careful not to use scary military terms such as virus amplification, lethal chain of transmission, crash and bleed, or major pucker factor.
From "The Hot Zone" by Richard Preston
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
