mercilessness vs reprieve

mercilessness

noun
  • The property of being merciless. 

reprieve

verb
  • To abandon or postpone plans to close, withdraw or abolish (something). 

  • To cancel or postpone the punishment of someone, especially an execution. 

  • To bring relief to someone. 

noun
  • A document authorizing such an action. 

  • Relief from pain etc., especially temporary. 

  • A cancellation or postponement of a proposed event undesired by many. 

  • The cancellation or postponement of a punishment. 

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