- (v.t.) To reverse, as what has been done; to annul; to bring to naught.
- (v.t.) To loose; to open; to take to piece; to unfasten; to untie; hence, to unravel; to solve; as, to undo a knot; to undo a puzzling question; to undo a riddle.
- (v.t.) To bring to poverty; to impoverish; to ruin, as in reputation, morals, hopes or the like; as, many are undone by unavoidable losses, but more undo themselves by vices and dissipation or by indolence.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). undo. Retrieved September 21, 2026, from http://smartdefine.org/undo/definitions/2076889 |
| Chicago | Webster's. 2011. "undo" http://smartdefine.org/undo/definitions/2076889 (accessed September 21, 2026). |
| Harvard | Webster's 2011, undo, Smart Define, viewed 21 September, 2026, <http://smartdefine.org/undo/definitions/2076889>. |
| MLA | Webster's. "undo" 28 May 2011. Web. 21 September 2026. <http://smartdefine.org/undo/definitions/2076889> |