Best definition
It’s a beer with so low-alcohol gradation that is not possible be drunken with it.

Fuck! Now, we are in Sweden and normal supermarkets can sell only waterbeer!
waterbeer: define #2
Water beerdrugs
The act of mixing the rest of your beer with a bottle of water when extremely intoxicated in attempts to avoid a massive hangover.
“Drink some fucking water!” (Marlin throws a bottle of water at Henry). “I havn’t finished my beer..” says Henry (proceeds to pour beer into bottle of water) “water beer mother fuckers! Dwipe up!!”