tepid vs unsharp

tepid

adj
  • Uninterested; exhibiting little passion or eagerness; lukewarm. 

  • Lukewarm; neither warm nor cool. 

unsharp

adj
  • dulled or intentionally blunt. 

  • out of focus; blurry. 

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

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