acquiescent vs refractory

acquiescent

adj
  • willing to acquiesce, accept or agree to something without objection, protest or resistance 

  • resting satisfied or submissive; disposed tacitly to submit 

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 acquiescent and refractory occurred in a corpus of books? (source: Google Ngram Viewer )