burnt sienna vs fire-crotch

burnt sienna

noun
  • dark reddish brown colour, like that of roasted sienna. 

adj
  • Of a dark reddish brown colour, like that of roasted sienna. 

fire-crotch

noun
  • A person who has red pubic hair. 

How often have the words burnt sienna and fire-crotch occurred in a corpus of books? (source: Google Ngram Viewer )