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-

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
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

intransitive verb

: to come open or apart
undoer noun

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 After gun fire, car chases, and a stabbing, Jadis was eventually undone like so many before her — by a zombie bite to the neck. Dalton Ross, EW.com, 24 Mar. 2024 Even if their minds are someday freed after Putin’s regime collapses, propagandistic brainwashing also takes time to undo. Brian Klaas, The Atlantic, 14 Mar. 2024 Rebuilding a Lost Waterfront: An heiress to the L.L. Bean fortune and a fan of the arts, Linda Bean has enlisted the artist Jamie Wyeth to help undo the damage of a fire in Port Clyde. Dave Philipps, New York Times, 8 Mar. 2024 President Biden's bid to sweep the Super Tuesday primaries was undone by an unlikely challenger, far from the U.S. mainland. Bill Chappell, NPR, 6 Mar. 2024 But after closing to within three points on three occasions in the third quarter, the Heat unraveled for a time, undone by poor shooting and an outburst by Michael Porter Jr., who scored 12 of his 30 in the third. Barry Jackson, Miami Herald, 1 Mar. 2024 It’s taken less than six years to undo it all and leave the once-great American company facing an uncertain future. Allison Morrow, CNN, 13 Mar. 2024 Rich and the rest of us know that the current border crisis is the fault of the Biden administration, which used its first weeks in power to undo the Trump administration’s executive orders and to institute its own on the border. Michael Brendan Dougherty, National Review, 12 Mar. 2024 Justin, 30, wore a Marine Serre shirt with the buttons undone. Michelle Lee, Peoplemag, 8 Mar. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'undo.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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

Dictionary Entries Near undo

Cite this Entry

“Undo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/undo. Accessed 29 Mar. 2024.

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

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!