attack dog vs white knight

attack dog

noun
  • A person who engages in rhetorical attacks on behalf of another. 

  • A dog used in the bloodsport of dogfighting. 

  • A person who fights physically on behalf of another. 

  • Any dog bred, trained or used for the purpose of attacking a target, either on command or on sight; trained either as a specialized form of police dog or a security force dog. 

white knight

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

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

  • Someone who unnecessarily defends someone else. 

  • 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 attack dog and white knight occurred in a corpus of books? (source: Google Ngram Viewer )