undo
verb
un·do ˌən-ˈdü 
ˈən-
undid ˌən-ˈdid
ˈən-
; undone ˌən-ˈdən ˈən-
; undoing ˌən-ˈdü-iŋ ˈən-
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 sense 3
intransitive verb
: to come open or apart
undoer
ˌən-ˈdü-ər
noun ˈən-
Synonyms
- demoralize
- emasculate
- paralyze
- unman
- unnerve
- unstring
See all Synonyms & Antonyms 
Example Sentences
You can't undo the past. The damage cannot be undone. He was undone by greed.
Recent Examples on the Web In a statement Tuesday, officials with the Spokane Police Department said the agency is grateful that the victims of Nash were afforded some justice while acknowledging nothing can undo the damage caused. 
Fox News, 31 Aug. 2022 Diving so deeply into intra-Democratic Party fights using right-wing Republican money will undo all its work to build broad bipartisan support for Israel. Jeremy Ben-ami, The New Republic, 27 July 2022 This brings us to the iOS 16 Messages update that lets users undo send and edit messages. Chris Smith, BGR, 7 June 2022 The governor’s push would undo a 2016 pact between legislators and then-Gov. Dustin Gardiner, San Francisco Chronicle, 25 Aug. 2022 When the holiday season is over, all of these hacks are super easy to undo. Alyssa Gautieri, Good Housekeeping, 19 Aug. 2022 The damage inflicted by the former President’s strategy will not be easy to undo. Julian Zelizer, CNN, 12 Aug. 2022 But that future presumes that drought, pests and wildfires associated with a rapidly warming climate don’t undo those efforts. Jason Mclachlan, The Conversation, 27 July 2022 Economic warfare can be almost as hard to undo as actual warfare. Jon Sindreu, WSJ, 5 Apr. 2022 See More
Fox News, 31 Aug. 2022 Diving so deeply into intra-Democratic Party fights using right-wing Republican money will undo all its work to build broad bipartisan support for Israel. Jeremy Ben-ami, The New Republic, 27 July 2022 This brings us to the iOS 16 Messages update that lets users undo send and edit messages. Chris Smith, BGR, 7 June 2022 The governor’s push would undo a 2016 pact between legislators and then-Gov. Dustin Gardiner, San Francisco Chronicle, 25 Aug. 2022 When the holiday season is over, all of these hacks are super easy to undo. Alyssa Gautieri, Good Housekeeping, 19 Aug. 2022 The damage inflicted by the former President’s strategy will not be easy to undo. Julian Zelizer, CNN, 12 Aug. 2022 But that future presumes that drought, pests and wildfires associated with a rapidly warming climate don’t undo those efforts. Jason Mclachlan, The Conversation, 27 July 2022 Economic warfare can be almost as hard to undo as actual warfare. Jon Sindreu, WSJ, 5 Apr. 2022 See More Word History
First Known Use
before the 12th century, in the meaning defined at transitive sense 1
Kids Definition
undo
verb
un·do ˌən-ˈdü
undid
-ˈdid
; undone -ˈdən
; undoing -ˈdü-iŋ
; undoes -ˈdəz
1
: untie sense 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.
undo
verb
1
as in to paralyze
to deprive of courage or confidence the sudden shriek undid the campers Synonyms & Similar Words
Relevance
- paralyze
- scare
- frighten
- intimidate
- emasculate
- unstring
- terrify
- unsettle
- unman
- weaken
- unnerve
- demoralize
- waste
- debilitate
- soften
- enfeeble
- neuter
- discourage
- disturb
- unhinge
- enervate
- unbalance
- sap
- dispirit
- terrorize
- perturb
- dishearten
- upset
- derange
- daunt
- tire
- faze
- dismay
- craze
- psych (out)
- discompose
- disquiet
- prostrate
- weird out
- madden
Antonyms & Near Antonyms
- nerve
- strengthen
- fortify
- encourage
- embolden
- hearten
2
as in to untie
to disengage the knotted parts of undo a tangled shoelace Synonyms & Similar Words
- untie
- unfasten
- loosen
- unbind
- unravel
- unlace
- disentangle
- untangle
- unlash
- unwind
- unbraid
- ravel
- unsnarl
- loose
Antonyms & Near Antonyms
- bind
- tie
- fasten
- knot
- lash
- wind
- braid
- entangle
- lace
- interweave
- snarl
- interlace
- tangle
3
as in to disturb
to trouble the mind of; to make uneasy the mere mention of the home invasion still had the power to undo her Synonyms & Similar Words
- disturb
- bother
- distract
- alarm
- worry
- concern
- anger
- derail
- agitate
- unsettle
- unhinge
- upset
- annoy
- perturb
- distress
- exercise
- plague
- haunt
- discomfort
- irritate
- ail
- confuse
- embarrass
- flurry
- frazzle
- dismay
- discompose
- aggravate
- rattle
- fuss
- disquiet
- weird out
- distemper
- exasperate
- discourage
- hagride
- harass
- pester
- vex
- rile
- get
- chafe
- bug
- put off
- gall
- irk
- put out
- harry
- fluster
- bedevil
- mortify
- freak (out)
- fret
- nettle
- alarum
- confound
- chivy
- peeve
- faze
- discomfit
- grate
- dispirit
- disconcert
- discountenance
- chivvy
- shake up
- pique
- dishearten
- jar
- demoralize
- daunt
- abash
- unnerve
- nonplus
Antonyms & Near Antonyms
- settle
- alleviate
- soothe
- compose
- calm
- allay
- quiet
- assuage
- tranquilize
- tranquillize
- placate
- appease
- conciliate
- mollify
- pacify
- propitiate
- extralities
- extrality
- extralogical
- extramarginal
- extramarital
- extramatrical
- extramatrimonial
- extramental
- extrameridian
- extrameridional
- extrametrical
- extramorainal
- extramorainic
- extramundane
- extramural
- extramurally
- extramusical
- extranei heredes
- extraneities
- extraneity
- extraneous
- extraneously
- extraneousness
- extraneousnesses
- extranet