contusion vs discoloration

contusion

noun
  • Synonym of bruising. 

  • Synonym of bruise. 

discoloration

noun
  • A discolored spot; a stain. 

  • The act of discoloring, or the state of being discolored; alteration of hue or appearance. 

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