dog eat dog vs rivalry

dog eat dog

adj
  • Ruthlessly acquisitive or competitive. Describes a business or other set of circumstances where people try to succeed at the expense of other people. 

rivalry

noun
  • The characteristic of being a rivalrous good, such that it can be consumed or used by only one person at a time. 

  • An ongoing relationship between (usually two) rivals who compete for superiority. 

  • Any competition between two or more things or factors. 

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