countermove vs differ

countermove

verb
  • To move in opposition or in retaliation. 

noun
  • A move in opposition or response to a preceding move. 

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. 

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