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]
 
 
/ʌnˈduː/ ( present participle undoing, past tense undid, past participle undone)
OPEN B2 to open something that is tied or fastened: I took off my hat and undid my coat. Can you undo this knot for me?Unfastening and opening
GET RID OF EFFECTS B2 to get rid of the effects of something that has been done before: Some of the damage caused by pollution cannot be undone.Removing and getting rid of thingsTaking things away from someone or somewhere
(Definition of undo from the Cambridge Learners Dictionary © Cambridge University Press)
Add Cambridge dictionaries to your browser to your website

Definitions of “undo” in other dictionaries

Word of the Day

bad/hard/tough luck

said to express sympathy with someone when something bad has happened to them

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