unclear vs unfathomable

unclear

adj
  • Not having a clear idea; uncertain. 

  • Not easy to see or read; indecipherable or unreadable. 

  • Ambiguous; liable to more than one interpretation. 

  • Not clearly or explicitly defined. 

verb
  • To undo the process of clearing. 

unfathomable

adj
  • Impossible to fathom or understand. 

  • Difficult to penetrate. 

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