(n.) One who oppresses; one who imposes unjust burdens on others; one who harasses others with unjust laws or unreasonable severity.

Simon Legree absolute monarch absolute ruler all-powerful ruler arrogator autarch autocrat bully caesar commissar czar despot dictator disciplinarian driver duce hard master intimidator iron hand martinet oligarch overlord persecutor pharaoh scourge slave driver stickler strong man taskmaster tormentor torturer tyrant usurper warlord