foggy vs ill-defined

foggy

adj
  • Obscured by mist or fog; unclear; hazy 

  • Being, covered with, or pertaining to fog (“tall grass etc that grows after, or is left after, cutting; moss”) 

  • Confused, befuddled, etc. 

ill-defined

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

  • Defined in an inconsistent way. 

How often have the words foggy and ill-defined occurred in a corpus of books? (source: Google Ngram Viewer )