arse vs caboose

arse

noun
  • 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. 

  • A stupid, pompous, arrogant, mean or despicable person. 

  • Used in similes to express something bad or unpleasant. 

verb
  • To be silly, act stupid or mess around. 

caboose

noun
  • The person or team in last place. 

  • A youngest child who is born after a long gap in time. 

  • A small sand-filled container used as an oven on board ship. 

  • The last car on a freight train, having cooking and sleeping facilities for the crew; a guard’s van. 

  • buttocks 

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