1. the cause of someone’s ruin or downfall
2. the process of reversing or canceling something that has been done

Examples

• His gambling addiction proved to be his undoing.
• Pride was the king’s undoing in the end.
• The undoing of the peace treaty took months of negotiation.
• She worked on the undoing of all the damage caused by the scandal.
• The politician’s lies led to his political undoing.
• The undoing of the merger required extensive legal work.
• Greed became the company’s undoing during the financial crisis.