about-turn vs backset

about-turn

noun
  • Total reversal of opinion or attitude. 

  • A turn of 180 degrees, typically in a military formation. 

verb
  • To turn 180 degrees, typically in a military formation. 

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. 

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