nameword vs sobriquet

nameword

noun
  • A designation or name given to an object, person or location. 

  • A noun. 

sobriquet

noun
  • A familiar name for a person or thing; a nickname (sometimes assumed by the person, but often given by others), that is descriptive. 

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