ill-defined vs unsharp

ill-defined

adj
  • Poorly defined; blurry, out of focus; lacking a clear boundary. 

  • Defined in an inconsistent way. 

unsharp

adj
  • out of focus; blurry. 

  • dulled or intentionally blunt. 

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