approve vs countersign

approve

verb
  • To officially sanction; to ratify; to confirm; to set as satisfactory. 

  • To make profit of; to convert to one's own profit — said especially of waste or common land appropriated by the lord of the manor. 

  • To consider worthy (to); to be pleased (with); to accept. 

  • To regard as good; to commend; to be pleased with; to think well of. 

countersign

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

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

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. 

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