perverse vs refractory

perverse

adj
  • Obstinately in the wrong; stubborn; intractable. 

  • Morally wrong or evil; wicked; perverted. 

  • Turned aside while against something, splitting off from a thing. 

  • Ignoring the evidence or the judge's opinions. 

  • Wayward; vexing; contrary. 

verb
  • To pervert. 

refractory

adj
  • Obstinate and unruly; strongly opposed to something. 

  • Not affected by great heat. 

  • Difficult to treat. 

  • Incapable of registering a reaction or stimulus. 

noun
  • A material or piece of material, such as a brick, that has a very high melting point. 

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