attrit vs back off

attrit

verb
  • To be reduced in quantity through attrition. 

  • To lose, or to kill, troops by attrition due to sustained firepower. 

  • To engage in attrition; to quit or drop out. 

  • To wear down through attrition, especially mechanical attrition. 

noun
  • One who voluntarily or involuntarily leaves a company; a termed employee. 

back off

verb
  • To lower the setting of. 

  • To become less aggressive, particularly when one had appeared committed to act. 

  • To move backwards away from something. 

  • You need to back off, or the situation could turn ugly. 

  • Used other than figuratively or idiomatically: see back, off. 

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