unclear vs undecided

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. 

undecided

adj
  • Open and not yet settled or determined. 

  • Uncommitted, not having reached a decision. 

noun
  • A voter etc. who has not yet come to a decision. 

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