smarten up vs unbend

smarten up

verb
  • To become less stupid or naive 

  • To wear smart clothes and look more stylish 

  • To make less stupid or naive 

unbend

verb
  • To cease to be bent; to become straight. 

  • To remove a bend so as to make, or allow to become, straight. 

  • To cast loose or untie 

  • To relax in exertion, attention, severity, or the like 

  • To release (a load) from a strain or from exertion; to set at ease for a time; to relax. 

  • To unfasten sails from the spars or stays to which are attached for use. 

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