brush off vs maintain

brush off

verb
  • To disregard (something), to dismiss or ignore (someone), as unimportant. 

  • Used other than figuratively or idiomatically: see brush, off. To remove something with a brush. 

maintain

verb
  • To declare or affirm (a clause) to be true; to assert. 

  • To keep up; to preserve; to uphold (a state, condition etc.). 

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