- simple past tense of undo.
verb (used with object), un·did, un·done, un·do·ing.
- 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.
- the past tense of undo
verb -does, -doing, -did or -done (mainly tr)
- (also intr) to untie, unwrap, or open or become untied, unwrapped, etc
- to reverse the effects of
- to cause the downfall of
- obsolete to explain or solve
v.Old English undon “to unfasten and open” (a window or door), “to unfasten by releasing from a fixed position,” from un- (2) + do (v.). The notion is of “to annul something that was done.” Related: Undone; undoing.