Dirty rat from a dirty sewer 

A person whom turns on you and screws you over for a girl, video games, or money. Any malicious act against you or your friends can qualify the perpetrator to be called a dirty rat from a dirty sewer.

Also can be called a 'filthy rat' or 'the filthiest rat' or 'the dirtiest rat from the dirtiest sewer' or just plain 'rat'

Guy 1- "That Chris is a dirty rat from a dirty sewer."
Guy 2- "Yeah, the filthiest rat from the dirtiest sewer."
Guy 3- "What a dirty rat!"

Dirty rat from a dirty sewer by Rat Keeper March 23, 2011

look like a rat peeping through a hedge 

Has a large unruly beard.

Liverpool (UK) slang

Get a shave, you look like a rat peeping through a hedge.

He looks like a rat peeping through a hedge.

look like a rat peeping through a hedge by Albert Stein February 6, 2008

Cly's-rat 

(n.) a person, most likely also a bust down, that goes to Clybourne bar (Cly's) at the University of Illinois at Urbana-Champaign on a weekly basis (most likely Thursday) to have pee and fecal matter fall on their heads from the pipes that will most certainly be leaking.

That girl goes to Cly's every Thursday - she's such a Cly's-rat. She'll probably give you dome, assuming you want some from her since her hair probably smells like dookey.

Cly's-rat by WeejeeKeejey October 22, 2010

bog rat 

a rat that lives down the toilet and eats poo.

Paul Wilson, thats fithly you bog rat!!!

bog rat by PAUL WHITTAKER December 15, 2003

dick rat 

A sketchy kid that deals drugs.

"Dude did you call dick rat yet?"
"yeah, he's gonna sell me an eighth for a pair of socks"

dick rat by mmasdfsdgjkabg September 30, 2006

Musk Rat 

The male equivalent of a hood rat. A skanky, sleazy male with no regard for standards who will sleep with anyone. (This is a large percentage of the male, college-age population)

Let's go find some musk rats!
That dude was a total musk rat.

Musk Rat by RatHunta99 November 3, 2010

Center rat 

People who think they are cool and hang out in West Hartford center. They are mostly kids who do drugs or do bad things.

center rat

Center rat by Hikey April 25, 2011