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90s Slang You Should Know


[uhn-did] /ʌnˈdɪd/
simple past tense of undo.


[uhn-doo] /ʌnˈdu/
verb (used with object), undid, undone, undoing.
to reverse the doing of; cause to be as if never done:
Murder once done can never be undone.
to do away with; erase; efface:
to undo the havoc done by the storm.
to bring to ruin or disaster; destroy:
In the end his lies undid him.
to unfasten by releasing:
to undo a gate; to undo a button.
to untie or loose (a knot, rope, etc.).
to open (a package, wrapping, etc.).
Archaic. to explain; interpret.
Origin of undo
before 900; Middle English; Old English undōn; cognate with Dutch ontdoen. See un-2, do1
Related forms
undoable, adjective
Can be confused
undo, undue. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for undid
Contemporary Examples
Historical Examples
  • Neville undid his railway rug and wrapped it round her, for the rain had made the air very chilly.

    The Old Pincushion Mrs. Molesworth
  • Cannie's fingers shook with excitement as she undid the knot.

    A Little Country Girl Susan Coolidge
  • Then he undid the clumsy knot with which the watchman had pinioned her hands.

    The Tangled Skein Emmuska Orczy, Baroness Orczy
  • She undid the fastening of her dress and slipped off the waist for me to see.

  • In desperate haste he undid the door, and rushing in, closed and barred it fast, to shut out the spell of the conquering Sword.

    The Shadow Witch Gertrude Crownfield
  • Sudden storms at just the wrong time delayed and undid the work.

    James B. Eads Louis How
  • But whether the action was right or wrong, and I am afraid it was not altogether right, I undid the packet.

    Lavengro George Borrow
  • He mounted with it to his dormitory and undid the covering in which it was encased.

    The Hero of Garside School J. Harwood Panting
  • A bystander came forward and undid the door, and a tall woman stood on the step of the coach looking around her.

    A German Pompadour Marie Hay
British Dictionary definitions for undid


the past tense of undo


verb (mainly transitive) -does, -doing, -did, -done
(also intransitive) to untie, unwrap, or open or become untied, unwrapped, etc
to reverse the effects of
to cause the downfall of
(obsolete) to explain or solve
Derived Forms
undoer, noun
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
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Word Origin and History for undid



Old English undon "to unfasten and open" (a window or door), "to unfasten by releasing from a fixed position," from un- (2) + do (v.). The notion is of "to annul something that was done." Related: Undone; undoing.

Online Etymology Dictionary, © 2010 Douglas Harper
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