pejorate vs sicken

pejorate

verb
  • To make or become worse; to deteriorate or to worsen. 

sicken

verb
  • To become weak; to decay; to languish. 

  • To fill with disgust or abhorrence. 

  • To become ill. 

  • To lower the standing of. 

  • To make ill. 

  • To be filled with disgust or abhorrence. 

  • To become disgusting or tedious. 

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