danger vs pitfall

danger

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

  • An instance or cause of likely harm. 

  • Exposure to likely harm; peril. 

pitfall

noun
  • A potential, unsuspected, hidden problem, hazard, or danger that is easily encountered but not immediately obvious. 

  • A type of trap consisting of a concealed pit in the ground, which the victim is supposed to fall into and not be able to get out from. 

  • An antipattern. 

  • Subsidence below ground in a mine, which can cause the ground level above to drop. 

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