cool cat vs serene

cool cat

noun
  • An individual who is at ease and self-assured; one who is calm and composed in interactions with others. 

  • A person who performs or appreciates jazz, especially one whose style of speech and movement is relaxed and rhythmic. 

serene

noun
  • Serenity; clearness; calmness. 

  • A fine rain from a cloudless sky after sunset. 

verb
  • To make serene. 

adj
  • Without worry or anxiety; unaffected by disturbance. 

  • Used as part of certain titles, originally to indicate sovereignty or independence. 

  • Calm, peaceful, unruffled. 

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