undo

• (US, UK)^[1] IPA^(key): /ʌnˈduː/

• Audio (Southern England):

  (file)

• Rhymes: -uː
• Homophone: undue (yod-dropping)

From Middle English undōn, from Old English ondōn, from Proto-West Germanic *andadōn (“to undo”), equivalent to un- +‎ do. Cognate with West Frisian ûndwaan, ûntdwaan (“to undo; rid”), Dutch ontdoen (“to undo”).

undo (third-person singular simple present undoes, present participle undoing, simple past undid, past participle undone) (transitive)

1. To reverse the effects of an action.

   Fortunately, we can undo most of the damage to the system by the war.

   • 1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene ii], page 4:

     Pro. […] it was a torment / To lay vpon the damn'd, which Sycorax / Could not againe vndoe ; it was mine Art, / When I arriu'd, and heard thee, that made gape / The Pyne, and let thee out.

   • 2011 October 15, Michael Da Silva, “Wigan 1 - 3 Bolton”, in BBC Sport‎^[1]:

     But Wigan undid their good work by conceding an avoidable second goal deep into first-half injury time.

   • 2019 April 6, Caleb Quinley, “Thailand: Anti-military party leader faces sedition charges”, in Al Jazeera‎^[2], Doha: Al Jazeera, retrieved 6 April 2019:

     And judging by how well the progressive and youth-favoured party did, many observers suspect this latest round of legal charges are a response to Future Forward's commitment to undo the legacy of military rule and undertake democratic reforms.

2. To unfasten.

   Could you undo my buckle for me?

3. (figuratively) To impoverish or ruin, as in reputation; to cause the downfall of.
   • 1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC:

     Woe is me, for I am undone!

• (reverse effects): cancel, reverse
• (unfasten): unbuckle, unbutton, untie, unzip

• (antonym(s) of “reverse effects”): redo
• (antonym(s) of “unfasten”): do up, button, button up, tie up, zip, zip up,

• → Welsh: andwyo

undo (plural undos)

1. (computing) An operation that reverses a previous action.

   How many undos does this program support?

undo

1. Misspelling of undue.

• undo on Wikipedia.Wikipedia

• udon

From unda (“a wave”).

• (Classical Latin) IPA^(key): [ˈʊn.doː]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈun̪.d̪o]

undō (present infinitive undāre, perfect active undāvī, supine undātum); first conjugation

1. to rise in waves
2. to overflow with, abound in
3. to wave, undulate

• Aromanian: undedz, undari
• → English: undate
• Italian: ondare
• Portuguese: undar
• Romanian: unda, undare
• Spanish: ondear

• “undo”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “undo”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• undo in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
• Carl Meißner, Henry William Auden (1894) Latin Phrase-Book‎^[3], London: Macmillan and Co.
  • a thing finds credence, is credible: aliquid fidem habet (vid. also fides under sect. VII., History)
    
• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “redound”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.

undo

1. flattery

• IPA^(key): /ˈunˌdoː/

undō

1. inflection of undōn:
   1. first-person singular present indicative
   2. singular present subjunctive
   3. singular imperative