j hammer
A person who judges you like you're the worst person ever. They're like a grumpy old man who thinks everyone is an idiot.
My neighbor is a J Hammer. He told me I'm the worst kid in the neighborhood for walking my dog at 10 p. m.
She's a J Hammer for saying I'm not good enough just because I like to play video games.
He's a J Hammer for thinking I'm a failure because I got a B on my math test.