Undo is done or undone?

1. What is undo in past tense?
2. What undo means?
3. Is the word undone correct?
4. What is being undone?

What is undo in past tense?

past tense of undo is undid.

What undo means?

transitive verb. : to open or loose by releasing a fastening. : to make of no effect or as if not done : make null : reverse.

Is the word undone correct?

undone adjective (NOT FASTENED)

unfastened: Why didn't you tell me my zip was undone!

What is being undone?

: not done : not performed or finished.