in question vs unclear

in question

adj
  • In doubt, under dispute. 

  • Under consideration, under discussion. 

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. 

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