Undo v. t. : To reverse, as what has been done; to annul; to bring to naught.

Undo 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.

Undo 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.

Example:
How do you Undo becoming a plant person in the sims?

Taxonomy
models, multi-user, flip, non-linear, free encyclopedia, implementation, the action, undone, activated, prototype, history, the user, undoing, visualizations, search, free dictionary, computer programs, last change.

Defination from the web:
Undo command is activated by pressing Ctrl-Z or Alt-Backspace. ... With non-linear undo, the action to be reverted can be freely picked from the action history list. ... When multiple users can edit the same document simultaneously, a multi-user undo is needed. ...