robber baron

noun2

1. •
   (US) Especially in the 19th and early 20th centuries, a business tycoon who had great wealth and influence but whose methods were morally questionable and often unethical.
2. •
   (historical) In Europe, an aristocrat who charged exorbitant fees or otherwise exacted money from people who journeyed across land or waterways which he controlled.

   • Men who made it a custom to travel the trail to Dawson, likened him to a robber baron, perched in his fortress and exacting toll from the caravans that used his ill-kept roads. — 1901