lest
Americanconjunction
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for fear that; so that (one) should not (used negatively to introduce a clause expressive of an action or occurrence requiring caution).
He kept his notes by his side lest faulty memory lead him astray.
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that (used after words expressing fear, danger, etc.).
There was danger lest the plan become known.
idioms
conjunction
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so as to prevent any possibility that
he fled the country lest he be captured and imprisoned
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(after verbs or phrases expressing fear, worry, anxiety, etc) for fear that; in case
he was alarmed lest she should find out
Etymology
Origin of lest
First recorded before 1000; Middle English leste, contraction of the lesse the, thi les the; late Old English the lǣste, earlier thȳ lǣs the, literally, “whereby less that” ( thȳ instrumental case of the demonstrative and relative pronoun, lǣs less, the conjunction)
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.
About the latter: Lest we forget, the U.S. spends more than $13,400 on healthcare per person, almost double the figure in other highly productive nations like Switzerland, Germany, Austria and Sweden.
From MarketWatch • Dec. 15, 2025
Lest we forget our past, America is the great democratic experiment precisely because it’s a land of immigrants.
From Los Angeles Times • Oct. 11, 2025
Lest you believe it’s about falling in love, she adds later on: “If you think I’m talkin’ ’bout romance / You’re not listening.”
From The Wall Street Journal • Sep. 30, 2025
Watching from the Mall, Grace Gothard, from Mitcham, made her Union Jack dress draped with the Ghanian flag while Satvinder Cubb, from Chingford made a frock made from two "Lest we forget" scarves.
From BBC • May 5, 2025
Lest these conclusions be misinterpreted, we should end this chapter with caveats against exaggerating two points: peoples’ readiness to accept better crops and livestock, and the constraints imposed by locally available wild plants and animals.
From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond
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.
