beg the question vs tergiversate

beg the question

verb
  • To sidestep or fail to address a question. 

  • To raise or prompt a question. 

  • To engage in the logical fallacy of begging the question (petitio principii). 

tergiversate

verb
  • To change sides or affiliation; to apostatize. 

  • To evade, to equivocate using subterfuge; to obfuscate in a deliberate manner. 

  • To flee by turning one's back. 

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