backstory vs dissimulation

backstory

noun
  • A fictitious account of a person's history designed to conceal their actual history and motives. 

  • The previous life and experiences of a person, especially a character in a dramatic work, but also a real-life person. 

  • A prequel. 

dissimulation

noun
  • The act of concealing the truth; hypocrisy or deception. 

  • Hiding one's feelings or intentions. 

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