In mythology, weeds growing in a lake which reach up and drag someone down to their death should they venture too far into the generally eerie looking, dimly lit water. They have a mind of their own and seemingly no not have humans best interests at heart.

An extended form of "weed" ie. Cannabis, used only because it has the word "weed" in it, in reality it has nothing to do with smoking grass.
Intellectual: "Beware: The lakesweed has dragged many a brave warrior down to their deaths."

Dumbass: "This lakesweed really is some fine sh*t."
by Debri O'Haullin May 18, 2008
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Weed growing in a lake. Loosely: Street name for bud Cannabis.
"Get me some lakesweed man, I'm gonna get stoned."
by Bareth April 24, 2006
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Term for Cannabis, mostly used in Glasgow in the mid 2000s.
I hard a hard day. Gonna have me some Lakesweed to help settle down.
by John G Grant August 13, 2011
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