Meaning of undo

un•do

1. to reverse the doing of; cause to be as if never done: Murder once done can never be undone.
2. to do away with; erase; efface: to undo the havoc done by the storm.
3. to bring to ruin or disaster; destroy: In the end his lies undid him.
4. to unfasten by releasing: to undo a gate; to undo a button.
5. to untie or loose (a knot, rope, etc.).
6. to open (a package, wrapping, etc.).
7. to explain; interpret.