charlatan vs impostor

charlatan

noun
  • A malicious trickster; a fake person, especially one who deceives for personal profit. 

impostor

noun
  • Someone who attempts to deceive by using an assumed name or identity. 

  • A sprite or animation integrated into a three-dimensional scene, but not based on an actual 3D model. 

  • A term referenced in an unusual grammatical person. 

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