back off vs hang out to dry

back off

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

  • To become less aggressive, particularly when one had appeared committed to act. 

  • To lower the setting of. 

  • To move backwards away from something. 

  • You need to back off, or the situation could turn ugly. 

hang out to dry

verb
  • Used other than figuratively or idiomatically: see hang, out, dry. 

  • To abandon someone who is in need or in danger, especially a colleague or one dependent. 

How often have the words back off and hang out to dry occurred in a corpus of books? (source: Google Ngram Viewer )