indigestible vs sickening

indigestible

adj
  • Difficult to accept; unpalatable. 

  • Difficult or impossible to digest. 

noun
  • Anything that is difficult to digest. 

sickening

adj
  • Causing sickness or disgust. 

  • Amazing, fantastic. 

noun
  • The act of making somebody sick. 

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