undoing

• IPA^(key): /ʌnˈduːɪŋ/

From Middle English undoinge, undoynge, ondoynge; equivalent to undo +‎ -ing.

undoing (plural undoings)

1. The act of loosening or unfastening
2. Ruin; defeat, (also) that which causes defeat or ruin.

   His fatal flaw was his undoing. In a sense he defeated himself.

   • 1912, Edgar Rice Burroughs, Tarzan of the Apes, Chapter 5:

     So far as the ape was concerned, Sabor reasoned correctly. The little fellow crouched trembling just an instant, but that instant was quite long enough to prove his undoing.

   • 2018 July 3, Phil McNulty, “Colombia 1 - 1 England”, in BBC Sport‎:

     The extra 30 minutes could not separate the sides and led to a nerve-shredding finale that has so often been England's undoing, with a dismal record of just one win in seven shootouts at major tournaments before this.

3. Annulment; reversal

From Middle English undoynge, undoand, from Old English undōnde (“undoing”), from Proto-Germanic *andadōndz, present participle of *andadōną (“to undo”). Cognate with Dutch ontdoend (“undoing”).

undoing

1. present participle of undo

• ounding