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”
G: The new boss, he keeps bragging about how he was part of a fraternity at college, is that lame or what?
OG: That's more than lame, that's phi beta lame?