indigestible vs rancid

indigestible

adj
  • Difficult to accept; unpalatable. 

  • Difficult or impossible to digest. 

noun
  • Anything that is difficult to digest. 

rancid

adj
  • Offensive. 

  • Rank in taste or smell. 

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