Pronunciation

change

Singular
undoing

Plural
undoings

  1. (usually singular) Somebody's undoing is the thing that causes them major problems, causes them to fail, or causes them to be discovered.
    He left behind a laptop computer loaded with details that would prove to be his undoing.

Plain form
undo

Third-person singular
undoes

Past tense
undid

Past participle
undone

Present participle
undoing

  1. The present participle of undo.