flatness vs roughness

flatness

noun
  • slim-tailedness or platykurticity 

  • The state of being bland : dullness 

  • Lack of bouquet and freshness of a wine, through too much aeration or infection with film yeasts 

  • The state of being flat 

  • The state of being two-dimensional; planar : planarity 

  • Mattness, the quality of a painted surface which scatters or absorbs the light falling on it, so as to be substantially free from gloss or sheen 

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