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12.
person who frequents the Colorado River.In particular the Lake Havasu/Parker Strip region. Commonly pays more attention to their boat than their wife,family,house etc. Almost always seen with a Coors Light in hand
Look at that guy. A piece of crap truck and a fugly house but a $75000.00 boat.

Yah,he must be a River Rat.
by bubbadave July 30, 2005
 
1.
Someone who either lives or represents El Rio, California. Usually low life wannabe gangsters who frequent Walmart stores and attempt to steal shit only to be caught and think they are bad ass mofos. They start fights only to run away from it.
River Rat: Sup foo i just got out for stealing from walmart
CO Boy: La Colonia Chiques Eastside, fuckin pussy.
*River Rat Runs*
CO Boy: Get back here bitch, 187 on a river rat.

COXCH
by 805 Beaner July 24, 2010
 
2.
A community of people that live along a river. Known as tight knit community that always sticks together and looks out for its children. Also, spend a lot of leisure time along the river, fishing, boating, ect. People that live along a river are proud to be called "river rats!"
river rat is a community/town/residence along a river
by river rat proud July 16, 2013
 
3.
Another reference to a USN SWCC (Special Warfare Combatant-Craft Crewman. SWCC are our nation’s premier force for operating and maintaining high-performance, state-of-the art craft on NSW combat missions in littoral (shallow-water) environments. These elite fast-boat operators are part of Naval Special Warfare Command, which is comprised of SEAL Teams, SEAL Delivery Vehicle (SDV) Teams and Special Boat Teams.

Highly-experienced “Brown Water” boat operators in support of SEAL missions.
The River Rats will be the support transporting the SEALS for the combat mission.
by snflwrtato October 21, 2011
 
4.
In poker, a fuck stick that has no pair and no draw that hits a card on fifth street "the river" to give him the best hand and suck out on another player and then brags about it. The amazing river card, making bad poker player look good since 1942. No pair, no draw, no problem!
plyr1: I called cause it was sooooted!
plyr2: You are a terrible fucking poker player river rat!
by Jim Etheridge December 10, 2005
 
5.
The go to move of bad poker players. A river rat is a player who, despite holding bad cards and hitting nothing on the flop, continues to bet right up until the fifth and final community card, the river card. More often than not noobs such as this usually get lucky on the river and insist on bragging about it despite the fact that their success was down do dumb luck and not skill. A river rat doesn't know when to fold and due to their ignorance pridefully consider themselves aggressive players rather than crap players, which is what they are. The most agonizingly annoying thing about river rats is that they have a tendency to be arrogant when they suck out, completely oblivious to the fact that they wouldn't last 2 seconds in a real tournament.
Guy 1 - Man check out that douche, he went right to the river with a stinking deuce seven off suit and sucked out running sevens.

Guy 2 - I know aye, and look at that smug smile on his face, acting like he's an expert poker player when really he's just a noob river rat tosser.
by stgi_dragons March 16, 2009
 
6.
In poker, the river is the fifth commmunity card to come up and the river rat is a person who called all wagers, with no apparent hand and a minute chance of winning, in order to catch some miracle card and 'river' any legitamate betting/raising hands.
I flopped a set, pounded it the whole way, and that river rat Mario called all the way just to hit a gut-shot.
by haymaka May 02, 2004
 
7.
An untidy woman with loose morals
a: hey I got with this hot bitch last night, her name was kristie!

B: yo dude she's a filthy river-rat!! DONT TELL ANYONE ELSE.
by stinkyface March 30, 2004