Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “undo”

See all translations

undo

verb [T]  /ʌnˈdu/ ( present participle undoing, past tense undid  /ʌnˈdɪd/, past participle undone  /ʌnˈdʌn/) us  

undo verb [T] (UNFASTEN)

to unfasten something that is closed or tied: He undid the top button of his shirt and loosened his tie.

undo verb [T] (REMOVE EFFECTS)

to remove the effects of something that happened earlier: It’s difficult to undo the damage caused by a father who abandons his child.
(Definition of undo from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of undo?
Add Cambridge dictionaries to your browser to your website

Definitions of “undo” in other dictionaries

Word of the Day

luck out

to be very lucky

Word of the Day

Think long and hard; the language of decisions

by Liz Walter,
January 28, 2015
One of the best ways (perhaps the best way) to improve your English is to learn how words go together in phrases, idioms, or other patterns such as verb/noun or adjective/noun pairs (often called ‘collocations’). This blog looks at some useful phrases and collocations connected with the subject of decisions, something we

Read More 

micro pig noun

January 26, 2015
an extremely small pig, bred to be a pet Micro pigs have become popular pets recently, with famous owners including Victoria Beckham, Paris Hilton and Olympic diver, Tom Daley.

Read More