differ vs recalcitrate

differ

verb
  • To have diverging opinions, disagree. 

  • Not to have the same traits or characteristics; to be unalike or distinct. 

  • To be separated in quantity. 

noun
  • A program that diffs, a diff. 

recalcitrate

verb
  • To express repugnance or opposition. 

  • To kick back; to kick against anything. 

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