Dictionary.com
Thesaurus.com
Showing results for undo. Search instead for undos.
Synonyms

undo

American  
[uhn-doo] / ʌnˈdu /

verb (used with object)

undid, undone, undoing
  1. to reverse the doing of; cause to be as if never done.

    Murder once done can never be undone.

  2. to do away with; erase; efface.

    to undo the havoc done by the storm.

  3. to bring to ruin or disaster; destroy.

    In the end his lies undid him.

  4. to unfasten by releasing.

    to undo a gate; to undo a button.

  5. to untie or loose (a knot, rope, etc.).

  6. to open (a package, wrapping, etc.).

  7. Archaic. to explain; interpret.


undo British  
/ ʌnˈduː /

verb

  1. (also intr) to untie, unwrap, or open or become untied, unwrapped, etc

  2. to reverse the effects of

  3. to cause the downfall of

  4. obsolete to explain or solve

"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

Other Word Forms

  • undoable adjective
  • undoer noun

Etymology

Origin of undo

First recorded before 900; Middle English; Old English undōn; cognate with Dutch ontdoen; un- 2, do 1

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.

It’s always easier to prevent bad behavior than to undo it.

From MarketWatch

Three months ago, another international team of scientists involving researchers in China, Spain and the U.K. also found they were able to undo physical brain damage in mice that resulted from Alzheimer’s.

From MarketWatch

Backed into a corner by the threat of a career-ending scandal—one that would not only undo her but also her blithely trusting editor — Elizabeth agrees to make the fantasy corporeal.

From Salon

At the center of the work is a way to undo a built in "brake" that tumors can trigger to keep immune cells from attacking.

From Science Daily

That was both his making and undoing, Chow said: "Otherwise, there would have been no Apple Daily. Of course, he wouldn't have ended up like this either."

From BBC