All 4 Uses of

plebeian
in
This Side of Paradise

This was fun for a while, but he essayed a cigarette in his exaltation, and succumbed to a vulgar, plebeian reaction.†
Chpt 1.1 *

There were three or four inconspicuous and quite startled boys from Lawrenceville, two amateur wild men from a New York private school (Kerry Holiday christened them the "plebeian drunks"), a Jewish youth, also from New York, and, as compensation for Amory, the two Holidays, to whom he took an instant fancy.†
Chpt 1.2

They filled the Jewish youth's bed with lemon pie; they put out the gas all over the house every night by blowing into the jet in Amory's room, to the bewilderment of Mrs. Twelve and the local plumber; they set up the effects of the plebeian drunks—pictures, books, and furniture—in the bathroom, to the confusion of the pair, who hazily discovered the transposition on their return from a Trenton spree; they were disappointed beyond measure when the plebeian drunks decided to take it as a joke; they played red-dog and twenty-one and jackpot from dinner to dawn, and on the occasion of one man's birthday persuaded him to buy sufficient champagne for a hilarious celebration.†
Chpt 1.2

They filled the Jewish youth's bed with lemon pie; they put out the gas all over the house every night by blowing into the jet in Amory's room, to the bewilderment of Mrs. Twelve and the local plumber; they set up the effects of the plebeian drunks—pictures, books, and furniture—in the bathroom, to the confusion of the pair, who hazily discovered the transposition on their return from a Trenton spree; they were disappointed beyond measure when the plebeian drunks decided to take it as a joke; they played red-dog and twenty-one and jackpot from dinner to dawn, and on the occasion of one man's birthday persuaded him to buy sufficient champagne for a hilarious celebration.†
Chpt 1.2

Definition:

of or belonging to common people -- often implying a lack of refinement

or:

an ordinary citizen of ancient Rome