Difference between Undo and Untie

Undo

Part of speech: verb

Definition: To reverse the effects of an action. To unfasten.

Example sentence: You can't undo a deportation.

Untie

Part of speech: verb

Definition: To loosen, as something interlaced or knotted; to disengage the parts of; as, to untie a knot.To free from fastening or from restraint; to let loose; to unbind.To resolve; to unfold; to clear.To become untied or loosed.