blockage vs impetus

blockage

noun
  • Synonym of constipation (“impairment of feces passage”). 

  • The thing that is the cause of such a state, blocking a passage. 

  • The state or condition of being blocked. 

  • Synonym of thrombosis, synonym of thromboembolism, or synonym of embolism. 

impetus

noun
  • The force or energy associated with a moving body; a stimulus. 

  • Anything that impels; a stimulating factor. 

  • An activity in response to a stimulus. 

  • A force, either internal or external, that impels; an impulse. 

  • A principle of motive force, held as exquivalent to weight times velocity by John Buridan, in an auxiliary theory of Aristotelian dynamics introduced by John Philoponus, describing projectile motion against gravity as linear until it transitions to a vertical drop and the intellectual precursor to the concepts of inertia, momentum and acceleration in classical mechanics. 

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