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



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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 The case of Shift, based in San Francisco, offers a look at the stomach-churning roller-coaster ride that undid all of their planning. NBC News, "Furloughs, a loan and disinfectant: How one tech startup is surviving the coronavirus crisis," 11 May 2020 The concern is that the desire to return to something like normal could undo the gains made by social distancing. Patrik Jonsson, The Christian Science Monitor, "Restless and ready to work, Georgia gets back to business," 27 Apr. 2020 Vendors and activists fear the coronavirus shutdown — a setback nobody saw coming — will undo the gains of a decade-long movement to decriminalize street vending in the city. Los Angeles Times, "L.A. street vendors fought 10 years for the right to sell. Then COVID-19 came along," 24 Apr. 2020 But William Reinsch, a senior adviser at the Center for Strategic and International Studies, said that the pandemic can't undo the technological advances that have dramatically boosted global trade over the past 50 years. Charles Riley, CNN, "30 days that brought the world to the brink of a depression," 21 Mar. 2020 Other reviewers had also reported issues with lost save files that undid hours of in-game progress. Kyle Orland, Ars Technica, "Ori and the Will of the Wisps," 12 Mar. 2020 Trisha Preston was transporting a patient in a mental health crisis in the back of her ambulance when suddenly the woman undid her seatbelt, jumped off the gurney and began attacking the veteran paramedic, punching her and pulling her hair. Gillian Flaccus, chicagotribune.com, "Paramedics have faced a rash of attacks from patients in Portland, Oregon. Now they’re getting self-defense training.," 11 Nov. 2019 Everything about these new uniforms was about undoing whatever happened at the Convention Center five years ago when there were players in orange hoods and a celebration worthy of a Lombardi Trophy. Dan Labbe, cleveland, "Browns new uniforms get it right with classic look," 15 Apr. 2020 Between each player’s turn, the diseases spread, undoing all your hard work. Harry Guinness, Popular Science, "Two-player board games that won’t make you hate the other person," 10 Apr. 2020

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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Time Traveler for undo

Time Traveler

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

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Statistics for undo

Last Updated

19 May 2020

Cite this Entry

“Undo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/undo. Accessed 25 May. 2020.

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More Definitions for undo


How to pronounce undo (audio)

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)


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

Thesaurus: All synonyms and antonyms for undo

Rhyming Dictionary: Words that rhyme with 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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