undo
Americanverb (used with object)
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undoes,
present (3rd person singular)
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undid,
past
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undone,
past participle
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undoing
present participle
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to reverse the doing of; cause to be as if never done.
Murder once done can never be undone.
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to do away with; erase; efface.
to undo the havoc done by the storm.
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to bring to ruin or disaster; destroy.
In the end his lies undid him.
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to unfasten by releasing.
to undo a gate; to undo a button.
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to untie or loose (a knot, rope, etc.).
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to open (a package, wrapping, etc.).
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Archaic. to explain; interpret.
verb
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(also intr) to untie, unwrap, or open or become untied, unwrapped, etc
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to reverse the effects of
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to cause the downfall of
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obsolete to explain or solve
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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undosimple
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undoessimple
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have undoneperfect
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has undoneperfect
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am undoingprogressive
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are undoingprogressive
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is undoingprogressive
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have been undoingperfect progressive
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has been undoingperfect progressive
Past
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undidsimple
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had undoneperfect
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was undoingprogressive
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were undoingprogressive
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had been undoingperfect progressive
Future
Etymology
Origin of undo
First recorded before 900; Middle English; Old English undōn; cognate with Dutch ontdoen; see origin at un- 2, do 1
Explanation
When you undo something, you make it invalid, like when governments undo treaties they've signed in the past. Another way to undo is simply to open: "I couldn't undo the knot on my sneakers, so I just slipped them off." When we undo something, we cancel out its results, or reverse them. You might try to undo the damage caused by your little sister's baseball, offering to replace your neighbor's broken window. Formally, this verb also means "cause downfall or ruin," so you could say, "His love of power will undo him in the end."
Vocabulary lists containing undo
Commonly Confused Words, List 3
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Commonly Confused Words, List 5
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Commonly Confused Words, List 11
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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.
See Examples For:
“No sentence can undo what his family and fellow deputies have carried for three years. My thoughts remain with them,” Ohlsen said in a statement.
From Los Angeles Times ● Oct. 1, 2026
This would effectively undo the 2025 rate cuts pushed by former Fed Chairman Jerome Powell, and would bring the central bank’s benchmark interest rate to a range of 4.25% to 4.5%.
From MarketWatch ● Sep. 11, 2026
“Maybe they need to look at the Costa del Whatsit and see what the cost is of tourism, because you can’t undo it once it’s done.”
From Slate ● Sep. 8, 2026
In a recent press briefing, Warsh said the Fed cannot use a "magic wand" to undo years of above-target inflation and must stay patient as price growth cools gradually.
From BBC ● Aug. 12, 2026
As much as I know that there are women who sit up through the night and undo patches of cloth that they have spent the whole day weaving.
From "Krik? Krak!" by Edwidge Danticat
The two-segment operating model undoes changes made by former chief executive Bernard Looney that were initiated as part of BP’s pivot to lower-carbon sources of energy.
From The Wall Street Journal ● Jun. 9, 2026
The decision undoes a ruling by US District Judge Maame E Frimpong in Los Angeles, who had said that there is a "mountain of evidence" showing the raids were violating the US Constitution.
From BBC ● Sep. 8, 2025
The property, listed at $39 million, is in the midst of renovation as its new owner undoes Ye’s head-scratching remodeling choices.
From Los Angeles Times ● Mar. 27, 2025
But positioning her as Ethan’s maybe-girlfriend — as if in obeisance to and at the same time defiance of some foundational rule of musical theater — undoes that work.
From New York Times ● Feb. 6, 2024
Everything that comes of morning undoes itself before nightfall: rooster walks back into forest, fires die down, birds coo-coo-coo, sun sinks away, sky bleeds, passes out, goes dark, nothing exists.
From "The Poisonwood Bible" by Barbara Kingsolver
Pamela Price was recalled in 2024 and replaced by Ursula Jones Dickson, who quickly undid many of Price’s signature policies.
From Los Angeles Times ● May 29, 2026
Much of the talk in the build up centred around Scotland's vulnerability in last 20 minutes, but it was a sluggish start that undid Gregor Townsend's side.
From BBC ● Feb. 7, 2026
Collette, who has two teenage children and lives in Sydney, discusses the altar she keeps at home, the power of birth order and the mohair sweater that nearly undid her.
From The Wall Street Journal ● Dec. 15, 2025
More aggressive fine print restrains other follies like the bond portfolio mismatches that undid California-based Silicon Valley Bank two years ago, says Davide Oneglia, director of European and global macro at TS Lombard.
From Barron's ● Oct. 25, 2025
George undid his bindle and brought out three cans of beans.
From "Of Mice and Men" by John Steinbeck
The league initially was neutral on Measure J, but “we do not believe a decision voters made at the ballot box should be undone because of an administrative or drafting error,” its statement said.
From Los Angeles Times ● Oct. 1, 2026
Here are four mistakes that generally can’t be undone and how to avoid them:
From The Wall Street Journal ● Sep. 29, 2026
"I understand that my false accusations have caused Mr Carter immense pain, suffering and damage that can never be fully undone."
From Barron's ● Sep. 25, 2026
That bet is now at risk of coming undone.
From MarketWatch ● Sep. 8, 2026
The paper heart comes undone, releasing its multicolored confetti over all of us like soft summer rain.
From "Lucky Broken Girl" by Ruth Behar
They beautifully elucidate Herzog’s complex notions of loneliness, reminding us that the heart’s desire to cling to something familiar and safe can also be its undoing.
From Salon ● Sep. 28, 2026
The appellate panel voiced serious doubts about undoing the consent decree at oral arguments in June.
From Los Angeles Times ● Aug. 19, 2026
A bloc of officials never thought the last two reductions were warranted, and some will now argue, in effect, for undoing them.
From The Wall Street Journal ● Jul. 13, 2026
"This is literally a matter of life and death, and risks undoing years of hard-won progress," he said.
From BBC ● Jul. 13, 2026
Unsleeping the Lord Odysseus lay, and roved in thought to the undoing of his enemies.
From "The Odyssey" by Homer
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.
