anyone that is below you. It can be socially, economically, linguistically, intelligently, whatever, it doesn't matter. It is up to you to decide and is on a case by case basis. Though if you are calling some rich bastard like Warren Buffet a pleb than your first name should probably be Sultan, to put it in perspective. It is best to use the word to describe someone that is not around though because then they are not there to prove you wrong with a fat stack of cash or by breaking out the queen's english or some crap. However, calling someone a pleb usually does not lead to a fight because they are likely too stupid to understand how much you have just insulted them. It is really best used to embrace your own current well-being, in good fun, with a underhanded insult on the dregs of society.
A guy walks out onto his pool deck in the middle of the afternoon with a tray full of double patron margaritas for his friends and lobster tails and steaks on the grill and says "I wonder what the plebs are doin today?" and then wonders if he turned on the security system at his beach house.
A word that is so played out by tools, douche bags, and advertising agencies to describe pointless crap that you can simply decide that someone is not a waste of space if they do not ever use it.
I have never heard of you using that shizz homey. That's why you're still down! You're the opposite of epic. Oh damn, I said it so please punch me in the face. I deserve it.
Unprotected sex from a guy's perspective.
Guy 1: Oh lord, what have I done?
Guy 2: Are you still thinking about last night?
Guy 1: Yeah dude, I just remembered, I went in barenutz on her.
Guy 2: You better smarten up!