jack·ass (n.)

1. A male ass or donkey.
2. A foolish or stupid person; a blockhead: "You’ve acted like an irrational jackass and it’s time you stopped" Margaret Truman.
3. When your truck runs out of gas and you pull it over to the side of the road, plop yourself down in a lawn chair (in the shade, of course) and commence to yack on your cell phone…

…while you let the woman, who was in the truck with you, take the gas can to nearest gas station (about a one mile round-trip hike.)