breathlessness vs expiration

breathlessness

noun
  • The state of being breathless or out of breath. 

  • Difficult or labored respiration, dyspnea, shortness of breath 

expiration

noun
  • The act or process of breathing out, or forcing air from the lungs through the nose or mouth 

  • That which is produced by breathing out, as a sound. 

  • A cessation, extinction, ending 

  • Emission of volatile matter; exhalation. 

  • The last emission of breath; death. 

  • The act of expiring. 

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