American English
/ənˈdu/
2 syllables · Stress the second syllable.
To reverse an action or change, so that its result is removed or the earlier situation returns.
Practice out loudTo reverse an action or change, so that its result is removed or the earlier situation returns.
Can I undo that change?
We cannot undo the damage.
undo a mistake · undo the damage · undo a change
undo + a mistake
undo + the effects of something
To open or loosen something that is fastened, by doing the opposite of fastening it.
She undid the top button.
He carefully undid the knot.
undo a button · undo a knot · undo a belt
undo + a button
undo + a knot
In a computer program, to cancel the last action and return the work to its earlier state.
Click Undo to remove the line.
I pressed Undo by mistake.
Undo button · undo command · undo an action
click Undo
use Undo to + verb
The past forms are undid and undone, not undoed. The third-person form is undoes.