Urban Dictionary:
N. A person who loves guns, especially big ones, and has lots of them, often to a ridiculous degree. Mel Gibson and Renee Russo's characters in Lethal Weapon 3 could be considered gun-bunnies.
Arnold Schwarzenegger's character in Commando, and all the commandos in Predator were better examples of gun bunnies. Often used in a mildly derisive manner.
Most frequently used this way in role-playing games (RPGs).
"And so the gun bunny whips out a rocket launcher and blasts that stupid neighbor's dog that wouldn't shut up."
