partisan vs true believer

partisan

noun
  • A fervent, sometimes militant, supporter or proponent of a party, cause, faction, person, or idea. 

  • An adherent to a party or faction. 

  • A long-handled spear with a triangular, double-edged blade having lateral projections, in some forms also used in boar hunting. 

  • A member of a band of detached light, irregular troops acting behind occupying enemy lines in the ways of harassment or sabotage; a guerrilla fighter. 

adj
  • Serving as commander or member of a body of detached light troops. 

  • Adherent to a party or faction; especially, having the character of blind, passionate, or unreasonable adherence to a party. 

  • Devoted to or biased in support of a party, group, or cause. 

true believer

noun
  • One who believes dogmatically in something regardless of evidence or even conclusive proof that the thing is false or was staged; one who has true-believer syndrome. 

  • Used other than figuratively or idiomatically: see true, believer. 

  • A strict follower of a doctrine. 

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