U-turn vs heel turn

U-turn

noun
  • A reversal of policy; an about-face, a backflip. 

  • A turn in a vehicle carried out by driving in a semicircle in order to travel in the opposite direction. 

verb
  • To shift from one opinion or decision to its opposite. 

  • To turn a vehicle in a semicircle so as to face the opposite direction. 

heel turn

noun
  • A turn executed by shifting weight on to the heel(s). 

  • A ballroom dancing move in which the dancer steps backwards, shifts their weight on to the back foot, and turns on the heel of that foot while holding the other foot close and parallel to it. 

  • A situation in which someone changes from being a villain into a hero. 

  • A radical change (of mind, opinion, etc.). 

  • An act of turning around abruptly, especially so that one faces the opposite direction. 

  • Synonym of heel/face turn (“a situation in which a wrestler previously identified as a villain changes to being considered a hero”) 

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