# undo

/ənˈdu/ (US) · /ʌndˈuː/ (UK)

Source: https://englishreference.com/word/undo
Updated: 2026-06-20

## Senses

### 1. to reverse an action

verb · CEFR B1

to cancel the effect of something that was done before.

For teachers: to reverse the effects or consequences of a previous action or decision.

- It is difficult to undo the damage caused by a bad reputation.
- The new administration sought to undo several of the previous government's most controversial environmental policies within its first hundred days.

### 2. to unfasten

verb · CEFR B1

to open something that is tied, buttoned, or zipped.

For teachers: to unfasten, untie, or loosen a physical connection or closure.

- He had to undo his seatbelt before he could get out of the car.
- She struggled to undo the intricate silk knots on the parcel without tearing the delicate decorative paper.

### 3. to cause ruin

verb · CEFR C1 · Literary

to cause someone to fail or lose their reputation.

For teachers: to bring to ruin or destruction; to cause the downfall of a person or entity.

- His greed would eventually undo him and his entire family.
- It was ultimately his stubborn refusal to listen to his advisors that would undo his long and otherwise successful career in diplomacy.

### 4. computing command

noun · CEFR B1

a button or command that cancels the last thing you did on a computer.

For teachers: a function within a software application that reverses the most recent operation and restores the document to its previous state.

- If you make a mistake while typing, just click undo.
- The application supports multiple levels of undo, allowing the designer to revert through several hours of incremental changes if necessary.

## Examples

- I made a mistake, so I clicked undo.
- If you accidentally delete a paragraph, you can usually undo the action by pressing a shortcut on your keyboard.
- The software allows users to undo multiple consecutive actions, providing a safety net for complex design tasks where a single error could compromise the entire project.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.