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.
Christa Pike, 50, on Wednesday survived two lethal injections of pentobarbital, a drug that suppresses nervous system activity.
From Barron's ● Oct. 4, 2026
And in states like Tennessee, which does not carry out many lethal injection executions, members of the execution team do not have the chance to perfect their skill by using it a lot.
From Salon ● Oct. 3, 2026
“The lethal injection chemical in the protocol has consistently been effective, and the protocol does not allow for additional procedures beyond what was carried out this evening.”
From The Wall Street Journal ● Oct. 1, 2026
"The lethal injection chemical in the protocol has consistently been effective, and the protocol does not allow for additional procedures beyond what was carried out this evening."
From BBC ● Oct. 1, 2026
In the absence of this protein, blood refuses to clot—and even a small nick or wound can accelerate into a lethal bleeding crisis.
From "The Gene" by Siddhartha Mukherjee
Definitions 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.
