refractory vs riotous

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. 

riotous

adj
  • Unrestrained and boisterous; degenerate or dissolute. 

  • Having the characteristics of a riot. 

  • Causing, inciting or taking part in a riot. 

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