plebeian (adj.)

"of or characteristic of the lower class," 1560s in a Roman historical sense, from Latin plebeius "belonging to the plebs," earlier plebes, "the populace, the common people" (as opposed to patricians, etc.), also "commonality; the mass, the multitude; the lower class," from PIE *ple-, from PIE root *pele- (1) "to fill." In general (non-historical) use from 1580s.

plebeian (n.)

"member of the lowest class," 1530s, from Latin plebius "person not of noble rank," from adjective meaning "of the common people" (see plebeian (adj.)).