Any animal of the Canine species that fits into a standard sized microwave.

Yapping, whining, biting ankles, and fitting into small purses are common amongst these animals.
KellEy: Check out my new puppy! She's a Chihuahua Yorkie mix.

Hailey: It's cute now, but just wait until it becomes a full-sized Rat Dog...

*KellEy hits Hailey
by HaileyM January 3, 2010
n. hot frankfurter (of unknown origin), wrapped in bacon, eaten in a long roll with grilled onions and peppers at 2:00am after the club.

The profiteers of these rather disgusting snacks set up outside of Los Angeles clubs, waiting for drunk patrons. They are notorious for cheating wasted customers of their change.
"Yo bitch, gimme my change...I ain't paying $10 for dis fucking rat dog!"
by AA Factory June 11, 2005
A very small dog, usually less than 10 or 15 pounds, usually short-haired but not always. Usually not of much practical use as a watchdog or protector, but kept mainly as a companion by little old ladies, gay men who don't like cats, and Paris Hilton. Includes such breeds as the Chihuahua, the Miniature Pinscher, the Rat Terrier and other similarly sized breeds.
"That rat dog is 3 years old and he isn't housebroken YET?"

"I swear, if that rat dog tries to bite me again, I'll stuff him in a sock and hang him up as cat bait!"
by For Whom the Bell Trolls June 13, 2006
A insult people would use on people that looks musty, dirty, or messy.
“Did you see Carson today?? He looks like a rat dog lmao.”
by Davae06 November 6, 2021
adj. when something, someone or an occurance is cheap, tight, mean, unfair etc. its rat dog. it can also be simply put as 'rat' or 'dog'
did cindy kick paul in the nuts? thats rat dog!
by Y2JiB July 11, 2008
A fat smelly rat dog is a small dog that’s fat, They are usually under 35 pounds and look like a rat. they also smell bad like really bad.
ewww your dog is such a fat smelly rat dog, it’s disgusting give he/r a shower! 🤮
by luna tuna September 21, 2020