Definition from Wiktionary, the free dictionary
- 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.
- A dog used in dogfighting; a bloodsport.
- A person who engages in rhetorical attacks on behalf of another.
2001, Mark Jaffe, The Gilded Dinosaur, page 146:
- It was, however, as Charles Darwin's alter ego, an attack dog for the theory of evolution, that Huxley gained his greatest notoriety.