Old school definition for the cops.
I got pulled over by the law dogs today.
A person who refuses to do something that might or might not be illegal simply because of the perceived implication that it is. This individual will often "call out" another person for performing said illegal behavior. He/she might also report illegal behavior to the popo.
ME: Hey G, want to take David to go gang banging?
FRIEND: Nah Cuz, Dave be a mega fucking Law Dog holmes.
ME: Hey man, want to shoot off some illegal fireworks?
LAW DOG: No way, those are illegal for a reason. They could hurt someone you know?
ME: Alright, then screw off.
LAW DOG: If you shoot those off, I'm going to have to report it. Sorry bro, but laws keep this country together.
To ply your mark with copious amounts of fast food before inviting your friend to participate with in a session of double penetration of said mark, and the insertion of foreign objects such as old dusty empty champagne bottles. From the Scottish family name Lawson and the term Rawdog. The "Lawdog".
Dude, go get that girl a sack of Taco Bell Grandes, grab that empty bottle of Dom, and get in here! She's wants the Lawdog!
a slut who's a lawyer
Look, Gio, here comes my girlfriend, the law dog
Someone involved in law enforcement; an unholder of the law.
You have the right to fuck off, lawdog.