acerbation vs danger

acerbation

noun
  • Exacerbation, aggravation, deterioration. 

  • Bitterness of feeling. 

danger

noun
  • Exposure to likely harm; peril. 

  • An instance or cause of likely harm. 

  • The stop indication of a signal (usually in the phrase "at danger"). 

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