contradict vs vary

contradict

verb
  • To be contrary to (something). 

  • To deny the truth or validity of (a statement or statements). 

  • To oppose (a person) by denying the truth or pertinence of a given statement. 

vary

verb
  • To be or act different from the usual. 

  • To make of different kinds; to make different from one another; to diversity; to variegate. 

  • To embellish; to change fancifully; to present under new aspects, as of form, key, measure, etc. See variation. 

  • Not to remain constant: to change with time or a similar parameter. 

  • To institute a change in, from a current state; to modify. 

  • To change with time or a similar parameter. 

  • To display differences. 

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