D-Bagery - Being so full of yourself that you think you're the best at

Being so full of yourself that you think you're the best at everything, even when you're clearly not.

My friend said he could beat anyone in a rap battle. He lost to a 6th grader. That was D-Bagery.

My teacher said I could have extra credit if I did my work. I didn't do it and still got extra credit. That was D-Bagery.

My cousin said his video game character was the best. It was a baby. That was D-Bagery.