countersign vs revoke

countersign

noun
  • A second signature added to a document to affirm the validity of the signature of the first person. 

  • The response to a sign or signal. 

verb
  • To sign on the opposite side of (a document). 

  • To add a second signature to a document, affirming the validity of the signature of another person. 

revoke

verb
  • To cancel or invalidate by withdrawing or reversing. 

noun
  • The act of revoking in a game of cards. 

  • 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. 

  • A renege; a violation of important rules regarding the play of tricks in trick-taking card games serious enough to render the round invalid. 

How often have the words countersign and revoke occurred in a corpus of books? (source: Google Ngram Viewer )