to reverse the doing of; cause to be as if never done

Murder once done can never be undone.

to do away with; erase; efface

to undo the havoc done by the storm.

to bring to ruin or disaster; destroy

In the end his lies undid him.

to unfasten by releasing

to undo a gate; to undo a button.

to untie or loose (a knot, rope, etc.).

to open (a package, wrapping, etc.).

Archaic . to explain; interpret.

verb

close , do , fasten , approve , permit , validate

verb

disengage , disentangle , free , loose , loosen , release , unbind , unblock , unbutton , unclose , unfasten , unfix , unlock , unloose , unloosen , unravel , unshut , unstop , untie , unwrapnotes:undo means to reverse an action or thing; undue means \'inappropriate\' or \'excessive\' , abate , abolish , abrogate , annihilate , annul , break , bring down , bring to naught , cancel , cramp * , craze , crimp * , decimate , defeat , demolish , destroy , have * , impoverish , injure , make waves , mar , negate , neutralize , offset , outfox , outmaneuver , outsmart , overreach , overthrow , overturn , quash , queer * , raze , reverse , ruin , screw up * , shatter , skin * , smash , spoil , stymie * , subvert , unbuild , undermine , unsettle , upset , vitiate , wipe out * , wrack , wrecknotes:undo means to reverse an action or thing; undue means \'inappropriate\' or \'excessive\' , blot , cross , delete , efface , erase , expunge , obliterate , rub , scratch , strike , wipe , x , slip , unclasp , bankrupt , break down , cross up , finish , sink , torpedo , wash up , wreck , attenuate , debilitate , devitalize , enfeeble , sap , unnerve , weaken , debauch , disconnect , disjoin , invalidate , nullify , open , outwit , uncover , unwrap , void