backset vs cave in

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. 

cave in

noun
  • The act of relenting. 

  • The location where something has caved in. 

  • The act of something collapsing or caving in. 

verb
  • To collapse inward or downward. 

  • To relent; to grant approval against one's initial will. 

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