brush off vs rebuff

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. 

rebuff

verb
  • To refuse; to offer sudden or harsh resistance; to turn down or shut out. 

  • To buff again. 

noun
  • Repercussion, or beating back. 

  • He was surprised by her quick rebuff to his proposal. 

  • A sudden resistance or refusal. 

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