rack rent
▸ noun an extortionate or very high rent, especially an annual rent equivalent to the full value of the property to which it relates.
▸ (rack-rent) verb [with object] dated exact an excessive or extortionate rent from (a tenant) or for (a property):
(rack-renting as noun) hundreds of thousands of peasants who hate corruption, rack-renting, and foreign intervention
(rack-renting as adjective) rack-renting landlords.