inflexibleness vs purposefulness

inflexibleness

noun
  • Obstinacy of will or temper; firmness of purpose that will not yield to importunity or persuasion; unbending pertinacity. 

  • The quality or state of being inflexible 

purposefulness

noun
  • The state of being purposeful. 

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