couth vs decorousness

couth

noun
  • Social grace, refinement, sophistication; etiquette, manners. 

  • A person with social graces; a refined or sophisticated person. 

adj
  • Agreeable, friendly, pleasant. 

  • Marked by or possessing a high degree of sophistication; cultured, refined. 

  • Comfortable; cosy, snug. 

decorousness

noun
  • The state or quality of being decorous. 

  • A decorous behaviour. 

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