Shop steward

[GarryDrold]

A officer in a [union], whose job it is to enforce a union contract, in addition to his regular job, with no extra pay. Viewed by [the employer] as a socialist puke, by lazy co-workers as a company [sellout], and by everyone else as insane.

[Britney]

a worker elected by workers in a factory or business to represent them in discussions with the management, usually a member of a trade union