undo

/ˈʌnˌdu/

/ənˈdu/

Other forms: undoing; undid

When you undo something, you make it invalid, like when governments undo treaties they've signed in the past. Another way to undo is simply to open: "I couldn't undo the knot on my sneakers, so I just slipped them off."

When we undo something, we cancel out its results, or reverse them. You might try to undo the damage caused by your little sister's baseball, offering to replace your neighbor's broken window. Formally, this verb also means "cause downfall or ruin," so you could say, "His love of power will undo him in the end."

Definitions of undo

1. verb

   cancel, annul, or reverse an action or its effect
   “I wish I could undo my actions”

   types:

   unbrace, unlace, untie

   undo the ties of

   unstrap

   remove the strap or straps from

   unhitch

   unfasten or release from or as if from a hitch

   unpick

   undo (the stitches) of (a piece of sewing)

   unfasten

   cause to become undone

   unbelt

   undo the belt of

   unstaple

   take the staples off

   unclip

   remove the clip from

   unbutton

   undo the buttons of

   unpin

   remove the pins from; unfasten the pins of

   disconnect, unplug

   pull the plug of (electrical appliances) and render inoperable

   unbraid

   undo the braids of

   unknot, unpick, unravel, unscramble, untangle

   become or cause to become undone by separating the fibers or threads of

   disentangle, unwind

   separate the tangles of

   unbuckle

   undo the buckle of

   open, spread, spread out, unfold

   spread out or open from a closed or folded state

   unwire

   undo the wiring of

   unloose, unloosen

   loosen the ties of

   unchain

   remove the chains from

   unlash

   untie the lashing of

   unzip

   open the zipper of

   unbend

   unfasten, as a sail, from a spar or a stay

   roll out, straighten

   unfold something that is wrapped up and spread it flat

   unyoke

   remove the yoke from

   unharness

   remove the harness from

   uncoil

   unwind or untwist

   divaricate

   spread apart

   exfoliate

   spread by opening the leaves of

   grass

   spread out clothes on the grass to let it dry and bleach

   butterfly

   cut and spread open, as in preparation for cooking

   uncross

   change from a crossed to an uncrossed position

   splay

   spread open or apart

   type of:

   change by reversal, reverse, turn

   change to the contrary
2. verb

   cause to become loose
   “undo the shoelace”

   synonyms: loosen, untie

   type of:

   alter, change, modify

   cause to change; make different; cause a transformation
3. verb

   remove the outer cover or wrapping of
   “undo the parcel”

   synonyms: unwrap

   type of:

   expose, uncover

   remove all or part of one's clothes to show one's body
4. verb

   cause the ruin or downfall of
   “A single mistake undid the President and he had to resign”

   type of:

   ruin

   destroy or cause to fail
5. verb

   deprive of certain characteristics
   synonyms: unmake

   types:

   destroy, destruct

   do away with, cause the destruction or undoing of

   kill

   destroy a vitally essential quality of or in

   do away with, eliminate, extinguish, get rid of

   terminate, end, or take out

   self-destroy, self-destruct

   do away with oneself or itself

   destruct

   destroy (one's own missile or rocket)

   end

   put an end to

   fracture

   interrupt, break, or destroy

   sweep away, wipe out

   eliminate completely and without a trace

   interdict

   destroy by firepower, such as an enemy's line of communication

   demolish, pulverise, pulverize

   destroy completely

   break apart, break up, disassemble, dismantle, take apart

   take apart into its constituent pieces

   dismantle, level, pull down, rase, raze, take down, tear down

   tear down so as to make flat with the ground

   eradicate, exterminate, extirpate, root out, uproot

   destroy completely, as if down to the roots

   dilapidate

   bring into a condition of decay or partial ruin by neglect or misuse

   demyelinate

   destroy the myelin sheath of