-ass vs -ity

-ass

suffix
  • Used to convert an adjective into a noun for a person who has that trait. 

  • Resembling. 

  • Used to intensify an adjective. 

-ity

suffix
  • Used to form a noun from an adjective; especially, to form the noun referring to the state, property, or quality of conforming to the adjective's description. 

  • Used to form other nouns, especially abstract nouns. 

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