un·do | \ˌən-ˈdü, ˈən-\
undid\ˌən-ˈdid, ˈən- \; undone\ˌən-ˈdən, ˈən- \; undoing\ˌən-ˈdü-iŋ, 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

c : seduce sense 3

intransitive verb

: to come open or apart

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Other Words from undo

undoer \ˌən-ˈdü-ər, ˈən- \ noun

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

But the process of undoing a regulation can take years and many of Pruitt’s other proposals like delaying new lead standards have already been overturned in courts. Umair Irfan, Vox, "Scott Pruitt is leaving behind a toxic mess at the EPA," 6 July 2018 Her son, Neil, was Mr Trump’s first nominee and could be charged with undoing his mother’s handiwork. The Economist, "A court with a solid conservative majority could reshape American life," 5 July 2018 That meeting, following revelations that the company used software to evade regulatory scrutiny, started the process of undoing what many onlookers saw as years of poor behavior on Uber’s part. Bloomberg, latimes.com, "Uber gets probationary license to operate in London as it tries to regain trust," 26 June 2018 That precise formula undid the 25-year-old rookie in a hurry Wednesday. Jeff Sanders, sandiegouniontribune.com, "Lucchesi's return brief as A's beat up Padres," 20 June 2018 For infants and parents who are breastfeeding, this can undo maternal bonding that's crucial for development. refinery29.com, "How Separating A Child From Their Parents Affects Their Health," 20 June 2018 Now the Trump administration is seeking to end the fight by undoing rules that restricted the controversial methods on federal land. NBC News, "The fight over Alaska's hunting rules runs deeper than using doughnuts to bait bears," 14 June 2018 Since taking office, Pruitt has been laser-focused on undoing environmental and safety rules proposed by former President Barack Obama’s administration. Philly.com, "EPA signals it will ban toxic chemical found in paint strippers," 10 May 2018 But as the tie encroached the final 10 minutes, Insigne came inches away from undoing all of the Three Lions' good work as the Napoli pace merchant latched onto a cheeky dink in behind the defense. SI.com, "VAR Controversy Gives Italy Late Penalty in Friendly Draw vs. England," 27 Mar. 2018

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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Statistics for undo

Last Updated

21 Oct 2018

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



English Language Learners Definition of undo

: to open or release (something) : to unfasten or loosen (something)

: to change or stop the effect of (something)

: to cause the failure of (someone or something)


un·do | \ˌən-ˈdü \
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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Comments on undo

What made you want to look up undo? Please tell us where you read or heard it (including the quote, if possible).


a state of commotion or excitement

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