ambition vs fire in the belly

ambition

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

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

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

fire in the belly

noun
  • The emotional stamina and vigor, passion, or inner drive to achieve something, to take action, etc. 

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