give the game away vs vouchsafe

give the game away

verb
  • To mistakenly reveal a secret. 

vouchsafe

verb
  • To disclose or divulge. 

  • To graciously give, to condescendingly grant a right, benefit, outcome, etc.; to deign to acknowledge. 

  • To receive or accept in condescension. 

How often have the words give the game away and vouchsafe occurred in a corpus of books? (source: Google Ngram Viewer )