undoing Definition

undo
verb undoes, undid, undone, undoing

tr & intr
1. To open, unfasten or untie (something).
2. To cancel or reverse the doing of something, or its effect or result; to annul.
3. facetious or literary
To bring about the downfall or ruin of someone or something.

Etymology: Anglo-Saxon undon.

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undoing
noun

1. The act or action of unfastening, untying, opening etc.
2a. Downfall or ruin;

Thesaurus: ruin, collapse, destruction, defeat, downfall, disgrace, weakness, humiliation, misfortune; Antonym: triumph, victory.
2b. The cause of it.

Idiom: be the undoing of someone

To bring about their downfall. Opposite of be the making of someone (at making).
Example: Alcohol will be the undoing of her