Observant vs couth

Observant

noun
  • A member of a Franciscan order that strictly observes the rules of St. Francis. 

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. 

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