cool as a cucumber vs peaceful

cool as a cucumber

adj
  • Calm and composed even in difficult or frustrating situations; self-possessed. 

peaceful

adj
  • Motionless and calm. 

  • Inclined to peace. 

  • Not at war; not disturbed by strife or turmoil. 

noun
  • a Muslim; especially a violent member of a radical Islamist group. 

How often have the words cool as a cucumber and peaceful occurred in a corpus of books? (source: Google Ngram Viewer )