opponent vs white knight

opponent

noun
  • One who opposes another; one who works or takes a position against someone or something; one who attempts to stop the progress of someone or something. 

  • The participant who opens an academic debate by putting forward objections to a theological or philosophical thesis. 

  • One who opposes another in words (in a dispute, argument or controversy). 

  • One who is opposed or objects (to a policy, course of action or set of ideas). 

  • One who opposes another physically (in a fight, sport, game, or competition). 

white knight

noun
  • Someone who unnecessarily defends someone else. 

  • An individual or corporation that intends to acquire another company in order to avert a hostile takeover. 

  • A man who defends a woman in debate etc. in an attempt to gain her favour. 

  • A mushroom of species Tricholoma album. 

  • A hero, savior, or righteous individual. 

verb
  • To unnecessarily defend someone, especially in an attempt to gain favour. 

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