casuist vs impostor

casuist

noun
  • A person who resolves cases of conscience or moral duty. 

  • One who is skilled in, or given to, casuistry. 

  • Someone who attempts to specify exact and precise rules for the direction of every circumstance of behaviour. 

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 casuist and impostor occurred in a corpus of books? (source: Google Ngram Viewer )