propriety vs rectitude

propriety

noun
  • Correctness in behaviour and morals; good manners, seemliness. 

  • The fact of possessing something; ownership. 

  • Suitability, fitness; the quality of being appropriate. 

rectitude

noun
  • Conformity to the rules prescribed for moral conduct; (moral) uprightness, virtue. 

  • Straightness; the state or quality of having a constant direction and not being crooked or bent. 

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