dullness vs slowness

dullness

noun
  • The quality of being slow of understanding things; stupidity. 

  • The quality of not perceiving or kenning things distinctly. 

  • The quality of being uninteresting; boring; humorless or irksome. 

  • Lack of interest or excitement. 

  • The lack of visual brilliance; want of sheen. 

  • bluntness. 

slowness

noun
  • The quality or state of being slow. 

  • A unit, the reciprocal of velocity, that delineates the amount of time required for an object to travel a given distance. 

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