undo

verb

un·​do ˌən-ˈdü 

ˈən-

undid ˌən-ˈdid 

ˈən-

; undone ˌən-ˈdən 

ˈən-

; undoing ˌən-ˈdü-iŋ 

ˈən-

; undoes

ˌən-ˈdəz, 

ˈən-

transitive verb

1

: to open or loosen by releasing a fastening

undid her jacket

2

: to make of no effect or as if not done : make null : reverse

The damage cannot be undone.

3

a

: to ruin the worldly means, reputation, or hopes of

a politician undone by scandal

b

: to disturb the composure of : upset

she's come undone

c

: seduce sense 3

intransitive verb

: to come open or apart

undoer

ˌən-ˈdü-ər 

ˈən-

noun

Synonyms of undo

• paralyze
• scare
• frighten
• intimidate

Examples of undo in a Sentence

You can't undo the past.

The damage cannot be undone.

He was undone by greed.

Recent Examples on the Web

But when renovating an 18th-century apartment on a side street in the Marais, architect Clément Lesnoff-Rocard boldly undid a number of alterations to the home over the years. — Felix Wagner, Architectural Digest, 11 July 2026

The Americans, meanwhile, beat Bosnia and Herzegovina in the Round of 32 to reach the Round of 16 for the first time since 2014, only to be undone by Belgium on July 6 in a match that was clouded by controversy (more on that below). — Daniel Ross Goodman, The Washington Examiner, 11 July 2026

Like Sir Richard Branson himself, Virgin lets the hair grow long and undoes a few buttons while still making savvy business decisions, like a boss. — Jp Brammer, Condé Nast Traveler, 10 July 2026

Newly introduced left back Joaquin Seys is so far containing the threat posed by Lamine Yamal but the Belgium defense will know that they can be undone by one moment of Spanish magic. — Aleks Klosok, CNN Money, 10 July 2026

Word History

First Known Use

before the 12th century, in the meaning defined at transitive sense 1

Rhymes for undo

• accrue
• ado
• ainu
• aircrew
• airscrew
• anew
• askew
• baboo
• babu
• bamboo
• beaucoup
• bijou

Kids Definition

undo

verb

un·​do ˌən-ˈdü 

ˈən-

undid -ˈdid  ; undone -ˈdən  ; undoing -ˈdü-iŋ 

1

: to make or become unfastened or loosened : open, untie

undo a knot

2

: to destroy the effect of : nullify, reverse

3

a

: to cause the ruin of

your stubbornness undid you

undone by greed

b

: to disturb the calmness of : upset

she's come undone

undoer noun