code name vs hypocoristic

code name

noun
  • A name used to clandestinely identify somebody or something, either for military or espionage purposes, or for commercial confidentiality. 

hypocoristic

noun
  • A nickname, especially one indicating intimacy and formed through a shortening of the original name. 

adj
  • Relating to a nickname, usually indicating intimacy with the person. 

  • Relating to baby talk. 

How often have the words code name and hypocoristic occurred in a corpus of books? (source: Google Ngram Viewer )