A person who works to oppose, hinder, or undermine the efforts or work of another person or group.
From counterwork + -er (agent noun suffix). Developed to describe individuals engaged in opposing labor, sabotage, or resistance efforts.
Historically, this described spies, saboteurs, or workers employed to prevent others from succeeding—it's especially interesting in labor history where companies would hire counterworkers to infiltrate unions and report on their activities.
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