j hammer
A loud, angry person who doesn't know anything but wants to tell you how bad you are. They're like a loudmouth with a megaphone and no brain.
My uncle is a J Hammer. He yells at me for getting a C instead of an A.
She was a J Hammer for saying I'm a bad dancer just because I tripped.
He's a J Hammer for thinking he's the best at everything just because he's loud.