Definition of undo in English:

undo

Syllabification: un·do
Pronunciation: /ˌənˈdo͞o
 
/

verb (undoes /-ˈdəz/, undoing; past undid; past participle undone)

[with object]
1Unfasten, untie, or loosen (something): the knot was difficult to undo
More example sentences
  • She noticed that not one of the men had loosened his tie and undone the top shirt button.
  • It was with a sense of the inevitable that I undid the ribbons, loosened the neck and let it slip down over my arms to the ground.
  • He had already slung his jacket and hat on to his bed and now he loosened his tie and undid the top two buttons of his dress shirt.
Synonyms
unfasten, unbutton, unhook, untie, unlace; unlock, unbolt; loosen, disentangle, extricate, release, detach, free, open; disconnect, disengage, separate
2Cancel or reverse the effects or results of (a previous action or measure): there wasn’t any way Evelyn could undo the damage
More example sentences
  • The Democrats are strongly opposed to the measures that undo many of the agreements that were struck during the original diesel package in 1999.
  • But this time, it has more to do with rectifying or even undoing some of the damage that resulted from the last international economic movement.
  • Their work may be undone as a result of the popular will.
Synonyms
2.1Cancel (the last one or more commands executed by a computer).
More example sentences
  • These range from nice functions like undoing and redoing a command, running spellcheck and printing a document.
  • Repeating the u command undoes each step in turn; the Ctrl-R keystroke puts them back (redo).
  • We undo the Ctrl-J with Ctrl-Shift - (that's Control-Shift-Hyphen) and type in the semicolon.
3 formal Cause the downfall or ruin of: Iago’s hatred of women undoes him
More example sentences
  • The Minstermen were neat and tidy in possession but, as has been the case on so many occasions this season, were undone by their final ball.
  • Perhaps all those rejections and ringing phones had undone him.
  • He was undone by a limited imagination and a moment of genius.
Synonyms
ruin, undermine, subvert, overturn, scotch, sabotage, spoil, impair, mar, destroy, wreck, eradicate, obliterate; cancel out, neutralize, thwart, foil, frustrate, hamper, hinder, obstruct
informal blow, put the kibosh on, foul up, scuttle

noun

Computing Back to top  
A feature of a computer program that allows a user to cancel or reverse the last one or more commands executed.
More example sentences
  • However Dreamweaver has really gone to town on this feature making it extremely easy to use, it allows users a virtually unlimited number of number of undos.
  • And the time they save in avoiding undos is invaluable.
  • Graphic designers love to hear that they can revert to any previous version of a document by using the undo feature in the web-based management interface.

Origin

Old English undōn (see un-2, do1).

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