lethal
Americanadjective
-
able to cause or causing death
-
of or suggestive of death
Related Words
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.
Federal authorities have said for years that neo-Nazi and anti-government militia groups pose the most active and lethal domestic threats, though recently authorities have noted increases in leftist and mixed-motive attacks.
From Salon • May 19, 2026
This is the Nebraska Biocontainment Unit, a high-tech facility designed to treat patients infected with highly lethal viruses or bacteria without transmitting them to hospital staff or the public.
From The Wall Street Journal • May 12, 2026
So lethal in the team’s first-round win over Edmonton and so ineffective in the first three games of this series, the power play finally clicked, with Beckett Sennecke and Alex Killorn scoring on the man-advantage.
From Los Angeles Times • May 11, 2026
Last month Takaichi's government relaxed the country's self-imposed rules to allow exports of lethal military hardware, seeking to grab a larger slice of the booming global market.
From Barron's • May 7, 2026
A pretty lethal looking Doberman Pinscher comes out the front door, followed by Kingston and another big dog.
From "Dry" by Neal Shusterman and Jarrod Shusterman
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.
