undoing/ʌnˈduːɪŋ/EtymologyFrom Middle English undoinge, undoynge, ondoynge; equivalent to undo + -ing.undoing means the act of loosening or unfastening. Lexicurio rates it Rare gem — a strength score of 76 out of 100.nounThe act of loosening or unfasteningRuin; defeat, (also) that which causes defeat or ruin.“In the end, his jealousy was his undoing.”Annulment; reversal