elbow joint vs obliquity

elbow joint

noun
  • Synonym of elbow. 

obliquity

noun
  • Axial tilt. 

  • Mental or moral deviation or perversity; immorality. 

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

  • 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 elbow joint and obliquity occurred in a corpus of books? (source: Google Ngram Viewer )