Originaly slang for someone who is Hydrocephalic , but which has now come to refer to any severe idiot or retarded individual.
Jones you mindless waterhead, how many times do I have to tell you not to stick the plastic bag over your head and play astronaut?!
by Stephen Daedalus June 10, 2007

Otler lacks common sense so Makanuchi Kim called him a waterhead.

The waterhead came into ventrilo and did not say a word.
by WooWoo Brothers April 18, 2006
Waterhead (noun): According to the outlaw-journalist Dr. Hunter S. Thompson, a waterhead is a weird (in the lowest sense of the word) individual, often of some social/political power that achieved said power through nepotism or by being a Greedhead.

It is implied that this weirdo has no brains & no real value other than to be Doomed. A waterhead behaves as a stooped, irrational blemish to his/her country.
From "Where the Buffalo Roam", based on the twisted legend of Hunter S Thompson:

The Gallow brothers -- Ernest and Julio -- party guys who had skinned a few Mexicans and forced them to carry them on their shoulders down to the pre-game tailgate parties at the colosseum. The Pepsi and Coka Cola bottlers of America -- Coke adds life; It's the real thing -- bombarded by missiles; flying flaming matchbook covers. The waterheads from General Motors up in the top seats where they belong; getting the worst of the pollution. All sorts of weird motherfuckers were at the game.
by Painted city March 13, 2013
Cant complete simple tasks or objectives without screwing them up and making things worse than they are.
Jonesy is such a waterhead
by M0nks July 30, 2006
hey did u see that waterhead.
by kelly derks June 10, 2006
a blundering idiot. a dork who knows everything and still only makes 9 dollars an hour at age 34. a retard who guns it after every stop, every time no matter what. buys everything from a 7-11. has a beacon score of 2. never loses an argument.
joe is a complete undiluted waterhead in its purest form. an absolute dork.
by cudadog July 13, 2008