Absolute moron. Also used to mean traitor to ones country, one who uses coercion through fear(also known as terrorism), Dick Cheney's puppet, total failure at all things(including failure, ironically), bigot, total loser, one who deprives the American people and global citizens of freedom, warmonger, dog dropper, one who finds a way to fall off a Segway scooter(which one of the selling points is you CAN'T fall off), someone with disregard for the English language, American vernacular or speech in general, or just generally a dumbass.
Benidict Arnold was a real Dubya.
Joe:Did you hear about that George W Bush?
Dave: You mean the one that can't tell sheep shit from coffee grounds?
Joe: Yep, thats the one.
I'm so sad my son/daughter/wife/husband/father/or all got killed because of that Dubya
You better do what Dubya says, or those baddies will come get you in your sleep!
George H. W. Bush: I'm sorry Barbara.
Barb Bush: Why George?
G. H. W. Bush: I really should've pulled out, then the country wouldn't have got Dubya'd.