2. One who is not mentally retarded but acts like it at most times
3. One who is to stupid to realize that he's stupid
Reader of Definition: "Man whoever posted this definition is a dipperoo!"
Writer of Definition: "You're a dipperoo now!"
The dipperoo hit the random boy in the back of the head with a baseball bat and demanded and apology.
The girl who got a 71 on her test and was proud of herself was a total dipperoo.