1. someone who doesn't have a clue, doesn't care that they don't have a clue and can maintain a constant stfu attitude about not having a clue while knowing that they don't have a clue. (see George W. Bush)
2. Anyone who both disagrees with your position and behaves in a way of which you do not approve. Usually referred to as such when not in immediate physical presence.
3. You, if you say it behind their back and can't say it to their face.
1. W is such a clueless asshole that he actually believes he's the Decider.
2. I wonder if Larry Craig ponders what a clueless asshole he is when he's taking a dump.
3. Hey, how's it going? Haven't seen you in a while. (While thinking to yourself: I haven't seen this clueless asshole in over a year. I guess my luck just ran out.)