half-caste vs impure

half-caste

noun
  • A person of mixed racial descent. 

adj
  • Of mixed racial descent. 

impure

adj
  • Unchaste; obscene (not according to or not abiding by some system of sexual morality) 

  • Containing undesired intermixtures 

  • Unhallowed; defiled by something unholy, either physically by an objectionable substance, or morally by guilt or sin 

How often have the words half-caste and impure occurred in a corpus of books? (source: Google Ngram Viewer )