backset vs disillusionment

backset

noun
  • A check; a relapse; a discouragement; a setback. 

  • Whatever is thrown back in its course, such as water. 

verb
  • To plow again in the fall; said of prairie land broken up in the spring. 

disillusionment

noun
  • A feeling of disappointment, akin to depression, arising from the realization that something is not what it was expected or believed to be, possibly accompanied by philosophical angst from having one's beliefs challenged. 

  • The act of freeing from an illusion; the state of being freed therefrom. 

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