backflip vs turn back

backflip

verb
  • To completely reverse a policy or opinion; perform a U-turn. 

  • To perform a backflip (rotation of body). 

noun
  • An act of rotating one's body 360 degrees in the backward direction. 

  • a total reversal in policy or opinion; a volte-face, a U-turn. 

turn back

verb
  • To reverse direction and retrace one's steps. 

  • To cause to reverse direction and retrace one's steps. 

  • To return to a previous state of being. 

  • To prevent or refuse to allow passage or progress. 

  • To adjust to a previous setting. 

  • To fold something back; to fold down. 

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