River weed refers to cannabis which has been inadvertently brought into a river, lake or any large body of water, making it incredibly soggy. Even after drying the weed out, it still tastes like shit.

The phrase "dirty old river weed" may be a vague throwback at the phrase "dirty old foot hash."
This dirty old river weed tastes like a wet dog.

Yeah, let's just roll up a river blunt!
by milk salad August 17, 2010
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