fallen angel vs regressor

fallen angel

noun
  • A (usually attractive) person, usually a woman, who has become deprived of money, status or morals. 

  • An angel who rebelled against God and was exiled from heaven. 

  • A bond that has declined in value due to credit deterioration to become a junk bond. 

regressor

noun
  • That which regresses, or causes regression. 

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