mulish vs recalcitrant

mulish

adj
  • Characteristic of a mule; stubborn, obstinate, or intractable 

recalcitrant

adj
  • Marked by a stubborn unwillingness to obey authority. 

  • Not viable for an extended period; damaged by drying or freezing. 

  • Unwilling to cooperate socially. 

  • Difficult to deal with or to operate. 

noun
  • A person who is recalcitrant. 

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