undo

verb

un·​do ˌən-ˈdü How to pronounce undo (audio)
ˈən-
undid ˌən-ˈdid How to pronounce undo (audio)
ˈən-
 ; undone ˌən-ˈdən How to pronounce undo (audio)
ˈən-
 ; undoing ˌən-ˈdü-iŋ How to pronounce undo (audio)
ˈən-
 ; undoes
ˌən-ˈdəz, 
ˈən-
Synonyms of undonext

transitive verb

1
: to open or loosen by releasing a fastening
undid her jacket
2
: to make of no effect or as if not done : make null : reverse
The damage cannot be undone.
3
a
: 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
undoer
ˌən-ˈdü-ər How to pronounce undo (audio)
ˈən-
noun

Synonyms of 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.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
However, the Legislature had just spent a decade trying to undo California’s over-incarceration of Black and brown people, and wasn’t interested in new laws that would potentially target those very folks. — Los Angeles Times, 31 July 2026 NurPhoto via Getty Images While fan protests have caused Sony to reverse course on many unpopular decisions over the years, PlayStation’s upcoming switch to all-digital games as of 2028 is not going to be undone. — Paul Tassi, Forbes.com, 31 July 2026 Bluntly, undoing two citywide votes on this basis is a democratic legitimacy problem. — Zack Defazio Farrell, San Diego Union-Tribune, 31 July 2026 By intimidating Black voters and galvanizing white Democrats who sought to undo the results of the Civil War, this violence served to effectively kill Reconstruction and the tangible promises of Black emancipation. — Jacob Ware, The Conversation, 31 July 2026 See All Example Sentences for undo

Word History

First Known Use

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

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

Rhymes for undo

See All Rhymes for undo

Browse Nearby Words

undivulged
undo
undoable
See all Nearby Words

Cite this Entry

“Undo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/undo. Accessed 4 Aug. 2026.

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Kids Definition

undo

verb
un·​do ˌən-ˈdü How to pronounce undo (audio)
ˈən-
undid -ˈdid How to pronounce undo (audio) ; undone -ˈdən How to pronounce undo (audio) ; undoing -ˈdü-iŋ How to pronounce undo (audio)
1
: to make or become unfastened or loosened : open, untie
undo a knot
2
: to destroy the effect of : nullify, reverse
3
a
: to cause the ruin of
your stubbornness undid you
undone by greed
b
: to disturb the calmness of : upset
she's come undone
undoer noun

More from Merriam-Webster on undo

Nglish: Translation of undo for Spanish Speakers

Last Updated: - Updated example sentences
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