refusal vs rejection

refusal

noun
  • The act of refusing. 

  • Depth or point at which well or borehole drilling cannot continue. 

rejection

noun
  • The act of rejecting. 

  • The state of being rejected. 

  • An immune reaction of a host organism to a foreign biological tissue, such as in an organ transplant. 

  • A blocked shot. 

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