unclear vs unsure

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. 

unsure

adj
  • uncertain 

  • unstable or precarious 

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