unsharp vs wear down

unsharp

verb
  • To sharpen (an image) by creating a blurred ("unsharp") negative as a mask, and then combining that mask with the original. 

adj
  • out of focus; blurry. 

  • dulled or intentionally blunt. 

wear down

verb
  • Used other than figuratively or idiomatically: see wear, down. 

  • To cause (someone) physical or mental fatigue. 

  • To eventually persuade or defeat (someone) through persistent effort. 

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