severity vs vehemence

severity

noun
  • The state of being severe. 

  • The degree of something undesirable; badness or seriousness. 

vehemence

noun
  • An intense concentration, force or power. 

  • A wild or turbulent ferocity or fury. 

  • Eagerness, fervor, excessive strong feeling. 

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