blacken vs debase

blacken

verb
  • To defame or sully. 

  • To make dirty. 

  • To cook (meat or fish) by coating with pepper, etc., and quickly searing in a hot pan. 

  • To become black. 

  • To cause to be or become black. 

debase

verb
  • To lower in character, quality, or value; to degrade. 

  • To lower the value of (a currency) by reducing the amount of valuable metal in the coins. 

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