demerit vs foible

demerit

noun
  • A quality of being inadequate; a fault; a disadvantage 

  • A mark given for bad conduct to a person attending an educational institution or serving in the army. 

  • That which one merits or deserves, either of good or ill; desert. 

foible

noun
  • A weakness or failing of character. 

  • A quirk, idiosyncrasy, or mannerism; an unusual habit that is slightly strange or silly. 

  • Part of a sword between the middle and the point, weaker than the forte. 

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