chafe vs gnaw away at

chafe

noun
  • Injury or wear caused by friction. 

  • Vexation; irritation of mind; rage. 

  • Heat excited by friction. 

verb
  • To have a feeling of vexation; to be vexed; to fret; to be irritated. 

  • To be worn by rubbing. 

  • To excite heat in by friction; to rub in order to stimulate and make warm. 

  • To excite passion or anger in; to fret; to irritate. 

  • To fret and wear by rubbing. 

  • To rub; to come together so as to wear by rubbing; to wear by friction. 

gnaw away at

How often have the words chafe and gnaw away at occurred in a corpus of books? (source: Google Ngram Viewer )