visionary vs will o' the wisp

visionary

noun
  • An impractical dreamer. 

  • Someone who has positive ideas about the future. 

  • Someone who has visions; a seer. 

adj
  • imaginary or illusory 

  • having vision or foresight 

  • idealistic or utopian 

  • prophetic or revelatory 

will o' the wisp

noun
  • A delusionary or otherwise unachievable goal that one feels compelled to pursue. 

  • A flickering light or lantern, especially over bogs, swamps or marshes, held by a supernatural creature who uses it to lure travelers at night to their demise. 

How often have the words visionary and will o' the wisp occurred in a corpus of books? (source: Google Ngram Viewer )