backtracking vs turnabout

backtracking

noun
  • The act of one who, or that which, backtracks; a retracing of one's steps. 

  • The usage of a runway as a taxiway, especially at private strips and smaller airports. 

  • The act of building all possible solutions to a problem incrementally, abandoning any candidate solution if it cannot lead to a valid solution. 

turnabout

noun
  • The act of turning about so as to face in the opposite direction 

  • A reversal of a decision or opinion etc; a change of mind or flip-flop 

  • A merry-go-round. 

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