Plebeian and Workaday

Plebeian adjective - Belonging to the class of people of low social or economic rank.

Workaday and plebeian are semantically related In some cases you can use "Workaday" instead an adjective "Plebeian".

Workaday adjective - Being of the type that is encountered in the normal course of events.

Plebeian and workaday are semantically related in usual topic. Sometimes you can use "Plebeian" instead an adjective "Workaday", if it concerns topics such as unimaginative.