decorum vs roughness

decorum

noun
  • Appropriate social behavior. 

  • A convention of social behavior. 

roughness

noun
  • A measure of how rough something is, such as a surface 

  • Abundance, especially of food. 

  • Roughage; coarse fodder. 

  • The property of being rough, coarseness. 

  • Something that is rough; a rough spot. 

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