asperity vs roughness

asperity

noun
  • The quality of having a rough or uneven surface. 

  • The quality of being harsh or severe in the way one speaks or behaves toward people. 

  • An area that protrudes from a surface. 

  • A section of a fault line with high friction, such that there is no movement along this part of the fault except during an earthquake. 

  • The quality of being difficult or unpleasant to experience. 

  • Something that is harsh and difficult to endure. 

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 asperity and roughness occurred in a corpus of books? (source: Google Ngram Viewer )