Someone judging a person that they do not know and with little to no information, giving them a derogatory label as a result of their bias. Thus, drawing a conclusion about the kind of person they are based on said label.
“That guy legit said I must be a slut if I drink tequila shots. He obviously judge labeled us from across the bar”
The annoying fat heffer of an office secretary that somehow always knows when someone has brought in food. You don't tell her about it, but when you open the box of donuts, there she is grubbing on them. Usually has stashes of assorted snacks such as Cheetos and Ring Dings in her desk drawers and cabinets.
Ralph: "Hey Brian, Kim brought in some bagels...come get one."
Brian: "Okay cool, I'll make sure I grab one before Judge Cheeto gets her paws on them."
Ralph: "Good idea...that bitch is ruthless when it comes to food."