hatstand vs unbelievable

hatstand

adj
  • Crazy, insane. 

noun
  • A device used to store hats upon, consisting of a vertical pole with a sturdy base to prevent toppling, and an array of pegs to hold the hats. 

unbelievable

adj
  • Amazing, incredible; so surprising it is almost unable to believe. 

  • Not to be believed. 

  • Implausible or improbable. 

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