ambition vs will o' the wisp

ambition

noun
  • A desire, as in (sense 1), for another person to achieve these things. 

  • Eager or inordinate desire for some object that confers distinction, as preferment, honor, superiority, political power, or fame; desire to distinguish one's self from other people. 

  • An object of an ardent desire. 

  • A personal quality similar to motivation, not necessarily tied to a single goal. 

verb
  • To seek after ambitiously or eagerly; to covet. 

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 ambition and will o' the wisp occurred in a corpus of books? (source: Google Ngram Viewer )