hot air vs obedience

hot air

noun
  • Air that has been heated, especially so as to function as the lifting agent of a hot-air balloon. 

  • Empty, confused, or exaggerated talk lacking meaning or substance; bluster. 

obedience

noun
  • The collective body of persons subject to any particular authority. 

  • A written instruction from the superior of an order to those under him. 

  • Any official position under an abbot's jurisdiction. 

  • The quality of being obedient. 

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