Dictionary

undo

verb un·do \ˌən-ˈdü, ˈən-\

: to open or release (something) : to unfasten or loosen (something)

: to change or stop the effect of (something)

: to cause the failure of (someone or something)

un·did\-ˈdid\un·done\-ˈdən\un·do·ing\-ˈdü-iŋ\

Full Definition of UNDO

transitive verb
1
:  to open or loose by releasing a fastening
2
:  to make of no effect or as if not done :  make null :  reverse
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 3
intransitive verb
:  to come open or apart
un·do·er \-ˈdü-ər\ noun
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First Known Use of UNDO

before 12th century
UNDID Defined for Kids

undo

verb un·do \ˌən-ˈdü\
un·did \-ˈdid\un·done \-ˈdən\un·do·ing \-ˈdü-iŋ\un·does \-ˈdəz\

Definition of UNDO for Kids

1
:  untie 2, unfasten <Can you undo this knot?>
2
:  to cancel the effect of :  reverse <The damage cannot be undone.>
3
:  to cause the ruin or failure of <He was undone by greed.>

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