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Past tense of undo.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


the past tense of undo
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014



v.t. -did, -done, -do•ing.
1. to reverse the doing of.
2. to repair or erase: to undo the damage.
3. to bring to ruin; destroy.
4. to unfasten or unlatch.
5. to untie.
[before 900]
un•do′a•ble, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


(anˈduː) past tense unˈdid (-ˈdid) : past participle unˈdone (-ˈdan) verb
1. to unfasten or untie. Could you undo the knot in this string?
2. to reverse, or destroy, the effect of. The evil that he did can never be undone.
unˈdoing noun
(the cause of) ruin or disaster. Gambling was his undoing.
unˈdone (-ˈdan) adjective
(of work, a task etc) not done, or not finished. I don't like going to bed leaving jobs/work undone.
Kernerman English Multilingual Dictionary © 2006-2013 K Dictionaries Ltd.
References in classic literature ?
Then I undid the mat, and he looked on the child, and laughed aloud.
Now, my father, I tell you that the marrow melted in my bones with terror, for if I undid the mat I feared he must see the child and then--"
"I have recovered the child, women," I said, as I undid the bundle.