refractory vs self-willed

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. 

self-willed

adj
  • Obstinate; strong-minded; unyielding to the desires, concern or opinions of others. 

  • Possessing self-will; determined to pursue one's own desires or adhere to one's own opinion.. 

  • He was so self-willed that he refused to do anything that did not grant instant satisfaction or direction. 

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