bewrayment vs tergiversation

bewrayment

noun
  • The act or process of bewraying; betrayal 

tergiversation

noun
  • The act of abandoning something or someone, of changing sides; desertion; betrayal. 

  • The act of evading any clear course of action or speech, of being deliberately ambiguous; equivocation; fickleness. 

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