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undid

American  
[uhn-did] / ʌnˈdɪd /

verb

  1. the simple past tense of undo.

undid British  
/ ʌnˈdɪd /

verb

  1. the past tense of undo

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Unlike the long-ago transition to the cloud, which undid many existing software firms, incumbents aren’t being complacent this time around.

From Barron's • Mar. 13, 2026

He was the 1920s utility entrepreneur who built the electricity revolution until the valuations that came along with it unraveled and undid him.

From The Wall Street Journal • Feb. 6, 2026

A 10-week study undid about 10 years’ worth of brain aging, they found.

From MarketWatch • Nov. 1, 2025

How did public health backslide so hard that it undid decades of progress—and is there any hope we can get back on track?

From Slate • Jul. 11, 2025

His breath caught in his throat, and tears began to form in his eyes as he undid the knot.

From "The Invention of Hugo Cabret" by Brian Selznick

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.