cold-blooded vs cool cat

cold-blooded

adj
  • Of a type of horse: tall and muscular, usually good-natured and suitable for heavy work. 

  • Lacking emotion or compunction. 

  • Having an unregulated body temperature; ectothermic. 

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. 

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