declaw vs worsen

declaw

verb
  • To make harmless. 

  • To surgically remove the claws of (an animal); to perform onychectomy on. 

worsen

verb
  • To make worse; to impair. 

  • To become worse; to get worse. 

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