grievance vs injustice

grievance

noun
  • Violation of regulations or objectionable behavior. 

  • A formal complaint, especially in the context of a unionized workplace. 

  • Feelings of being wronged; outrage. 

  • A wrong or hardship suffered, which is the grounds of a complaint. 

  • A complaint or annoyance. 

  • Something which causes grief. 

injustice

noun
  • Violation of the rights of another person or people. 

  • Absence of justice; unjustice. 

  • Unfairness; the state of not being fair or just. 

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