undo

Short definition from Wiktionary

Verb

1. 1
   To reverse the effects of an action.
2. 2
   To unfasten.
3. 3
   To impoverish or ruin, as in reputation; to cause the downfall of.

Noun

1. 1
   An operation that reverses a previous action.

Adjective

1. 1
   Misspelling of undue.