ass vs backside

ass

noun
  • The buttocks. 

  • The anus. 

  • A stupid person. 

  • Sex; a person to have sex with; with vulgar emphasis on their corporeality (their body) over their personhood. 

  • Used in similes to express something bad or unpleasant. 

  • A person; the self; (reflexively) oneself or one's person, chiefly their body. By extension, one's personal safety, or figuratively one's job, prospects, etc. 

  • Any of several species of horse-like animals, especially Equus asinus, the domesticated of which are used as beasts of burden. 

adj
  • Of low quality; bad. 

particle
  • Synonym of -ass (“used to intensify an adjective”) 

backside

noun
  • A person's buttocks. 

  • Used other than figuratively or idiomatically: see back, side. 

  • The back side of an estate: the backyard and outbuildings behind a main house, especially (UK dialect, euphemistic) an outhouse. 

  • The reverse or opposite of anything. 

adj
  • Used other than figuratively or idiomatically: see back, side. 

  • Approaching an obstacle backward 

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