informal and derogatory:
an ordinary person, especially one from the lower social classes
The noun pleb, which appeared in the late 18th century, is a shortened form of plebeian.
The plural plebs, meaning the common people, dates back to the late 16th century. It is from Latin plebs/plebis, denoting the general body of citizens at Rome, the plebeian class, as opposed to the patricians, senators and knights. By extension, it also meant the great mass and, with notion of contempt, the populace, the mob.
One of the first users of plebs in English was the poet George Daniel (1616-57) in The Author (1647):
For ’tis an Easier Thing
To make Trees Leape, and Stones selfe-burthens bring
(As once Amphion to the walls of Thæbes,)
Then Stop the giddie Clamouring of Plebs.
The singular pleb is first attested in Life’s Vagaries (1795), a comedy by the Irish actor and playwright John O’Keefe (1747-1833):
– Dickins: Sir, your ill manners, in your own house, are equal to your impudence in bringing me into it for nothing.
– Sir Hans Burgess: Impudence, you vulgar man! it’s well you are in my house, or, by the hand of this body, I’d have you pitched out of window.
– Dickins: Pitch me, you hard-headed old fool! if Torrendel was to behave so, I’d—
– Sir Hans Burgess: I shall choak.—(rings) You’re under my roof, you pleb—so say what you will—Robin Hoofs!
– Dickins: Damn your hoofs, and your horns, Sir! I can quit your house myself. You’re as impudent as Torrendel.
On 19th September 2012 began what has been known as the Plebgate. During a row with police officers who would not let him cycle through Downing Street’s main gate, the Conservative MP Andrew Mitchell, then the government’s chief whip, allegedly called them plebs.
front page of the newspaper The Sun – Friday 21st September 2012
listen here to patronising remarks in Is the word ‘pleb’ an insult?
on BBC Radio 4 – Monday 24th September 2012
In American English, pleb, or plebe, is an informal and often derogatory name for a newly entered cadet at a military or naval academy. The Military and Naval Magazine of the United States of October 1833 published A Pleib’s account of himself, which contains the following:
I was drilled two hours before breakfast, in the wet grass, and was so proficient as to advance as far as the oblique step right and left, and my drill master, a young stripling, told me I was not so “gross” as most other pleibs, the name of all new cadets.