bitter pill vs disgruntlement

bitter pill

noun
  • Used other than figuratively or idiomatically: see bitter, pill. 

disgruntlement

noun
  • The state of being disgruntled, usually displayed in a stereotypical form such as frowning and annoyance; the acts of sulky dissatisfaction. 

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