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"
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
A Long Way Gone
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Silent Spring
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
“Our overt preference is to buy American,” Defense Secretary Pete Hegseth said last year as he introduced Drone Dominance, a $1.1 billion Pentagon program to purchase small, lethal drones.
From The Wall Street Journal ● Oct. 13, 2026
One can only hope that this disturbing episode will cause reconsideration of our half-century-long experiment with lethal injection, but I’m not so sure.
From The Wall Street Journal ● Oct. 12, 2026
Other states have also struggled with executions by lethal injection in recent years.
From Los Angeles Times ● Oct. 9, 2026
The Pike case is now in uncharted territory, as Pike is believed to be the only person to have survived an execution attempt by lethal injection.
From BBC ● Oct. 8, 2026
Hrv is a highly lethal but not very infective Biosafety Level 2 agent.
From "The Hot Zone" by Richard Preston
![]()
Random Word
Spin the wheel and learn a new word!
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.