undo

verb
un·​do | \ ˌən-ˈdü How to pronounce undo (audio) , ˈən-\
undid\ ˌən-​ˈdid How to pronounce undid (audio) , ˈən-​ \; undone\ ˌən-​ˈdən How to pronounce undone (audio) , ˈən-​ \; undoing\ ˌən-​ˈdü-​iŋ How to pronounce undoing (audio) , ˈən-​ \

Definition of undo

transitive verb

1 : to open or loose by releasing a fastening
2 : to make of no effect or as if not done : make null : reverse
3a : to ruin the worldly means, reputation, or hopes of a politician undone by scandal
b : to disturb the composure of : upset she's come undone

intransitive verb

: to come open or apart

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Other Words from undo

undoer \ ˌən-​ˈdü-​ər How to pronounce undoer (audio) , ˈən-​ \ noun

Synonyms & Antonyms for undo

Synonyms

demoralize, emasculate, paralyze, unman, unnerve, unstring

Antonyms

nerve

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Examples of undo in a Sentence

You can't undo the past. The damage cannot be undone. He was undone by greed.
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Recent Examples on the Web

Critics of the new immunization law hope to undo it with the 2020 ballot, but their path could be costly and difficult. Julia Wick, Los Angeles Times, "Newsletter: Essential California Week in Review: End-of-session rush in Sacramento," 14 Sep. 2019 But ongoing civil unrest in Hong Kong could rekindle proposals in Washington to undo it. Bill Campbell For Cnn Business Perspectives, CNN, "Ongoing unrest in Hong Kong risks dragging down the global economy," 6 Sep. 2019 But phone calls from the New Canaan mothers undid her. Sarah Schweitzer, The Atlantic, "The Lunch Ladies of New Canaan," 15 Aug. 2019 The Presidio Trust has been trying to undo that damage since 1994, when the Army turned the land over to the National Park Service and the trust took charge of the interior 80% of the park. Peter Fimrite, SFChronicle.com, "On the edge of SF’s Presidio, restoring a watershed will benefit nature and humans," 5 Aug. 2019 The Trump administration has been working since last year to undo it and to strip California of its ability under the federal Clean Air Act to set its own tailpipe standards. Paul Rogers, The Mercury News, "How California has blocked Trump’s environmental rollbacks," 27 July 2019 Significantly, neither the Republican Eisenhower Administration nor the Tory governments that returned to power in the 1950s tried to undo many of these changes, which enjoyed consensus support well into the 1970s. David Kaiser, Time, "Donald Trump and Boris Johnson Rode the Same Wave Into Power. History Suggests the Parallels Won’t Stop There," 26 July 2019 Love is often a bittersweet thing in his songs, a force that undoes us. John Adamian, courant.com, "New Wave icons Elvis Costello, Blondie at Mohegan," 12 July 2019 Hagglund's own goal followed soon after, but Houston had already undone itself earlier in the contest. Pat Brennan, Cincinnati.com, "FC Cincinnati hangs on for 3-2 win against Houston Dynamo," 6 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'undo.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of undo

before the 12th century, in the meaning defined at transitive sense 1

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Dictionary Entries near undo

undivined

undivinely

undivulged

undo

undoable

undocile

undock

Statistics for undo

Last Updated

7 Oct 2019

Look-up Popularity

Time Traveler for undo

The first known use of undo was before the 12th century

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More Definitions for undo

undo

verb

English Language Learners Definition of undo

: to open or release (something) : to unfasten or loosen (something)
: to change or stop the effect of (something)
formal : to cause the failure of (someone or something)

undo

verb
un·​do | \ ˌən-ˈdü How to pronounce undo (audio) \
undid\ -​ˈdid \; undone\ -​ˈdən \; undoing\ -​ˈdü-​iŋ \; undoes\ -​ˈdəz \

Kids Definition of undo

1 : untie sense 2, unfasten Can you undo this knot?
2 : to cancel the effect of : reverse The damage cannot be undone.
3 : to cause the ruin or failure of He was undone by greed.

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More from Merriam-Webster on undo

Rhyming Dictionary: Words that rhyme with undo

Thesaurus: All synonyms and antonyms for undo

Spanish Central: Translation of undo

Nglish: Translation of undo for Spanish Speakers

Britannica English: Translation of undo for Arabic Speakers

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