cryptology vs obliquity

cryptology

noun
  • Secret or enigmatical language. 

  • The science or study of mathematical, linguistic, and other coding patterns and histories. 

  • The practice of analysing encoded messages, in order to decode them. 

obliquity

noun
  • The quality of being obscure, oftentimes willfully, sometimes as an exercise in euphemism. 

  • Axial tilt. 

  • Mental or moral deviation or perversity; immorality. 

  • The quality of being oblique in direction, deviating from the horizontal or vertical; or the angle created by such a deviation. 

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