hesitate vs pull back

hesitate

verb
  • To utter with hesitation or to intimate by a reluctant manner. 

  • To stammer; to falter in speaking. 

  • To stop or pause respecting decision or action; to be in suspense or uncertainty as to a determination. 

pull back

verb
  • Used other than figuratively or idiomatically: see pull, back. 

  • To retreat. 

  • To pass (the ball) into a position further from the attacking goal line. 

  • To score when the team is losing. 

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