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

Outer Banks season 5 has arrived and ended the series on a rather conclusive note, indicating there won’t be a secret sixth season to bring things back and undo the series finale. — Paul Tassi, Forbes.com, 22 Aug. 2026

But no state law can undo the psychological damage of a president telling millions of parents, days before the first bell, that their pediatrician’s recommendations are dangerous. — Chuka Onuh, Chicago Tribune, 20 Aug. 2026

To that, Deadline reached out to both the campaigns of Steve Hilton and Xavier Becerra for comment on both the efforts to undo the tax credits cap and the ambitions for a post-comprehensive production credit. — Dominic Patten, Deadline, 20 Aug. 2026

That distinction means the same body that appointed LeVota cannot simply vote to undo that appointment and replace him. — Ben Wheeler, Kansas City Star, 19 Aug. 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