A Quick and Simple Dictionary

revoke

1. Verb.  (transitive) To cancel or invalidate by withdrawing or reversing.
2. Verb.  (intransitive) To fail to follow suit in a game of cards.
3. Noun.  The act of revoking in a game of cards.
4. Noun.  A renege; a violation of important rules regarding the play of tricks in trick-taking card games serious enough to render the round invalid.
5. Noun.  A violation ranked in seriousness somewhat below overt cheating, with the status of a more minor offense only because, when it happens, it is usually accidental.