lackluster vs unsharp

lackluster

adj
  • Having no shine or lustre; dull. 

  • Not exceptional; not worthy of special merit, attention, or interest; having no vitality. 

  • Lacking brilliance or intelligence. 

noun
  • Lack of brightness or points of interest. 

  • A person or thing of no particular brilliance or intelligence. 

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 lackluster and unsharp occurred in a corpus of books? (source: Google Ngram Viewer )