flexion vs inclination

flexion

noun
  • The state of being bent or flexed. 

  • Deviation from straightness. 

  • The act of bending a joint, especially a bone joint; the counteraction of extension. 

inclination

noun
  • A physical tilt or bend. 

  • A tendency. 

  • The angle of intersection of a reference plane 

  • A slant or slope. 

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