Slumlord

A "slumlord" (or "slum landlord") is the owner of a property in disrepair who lets to tenants. The term is American and dates after the Second World War (1945--).

Our first known citation is from Chicago, but the term may have originated in New York City. It was used often in the 1960s and 1970s when New York City had grave fiscal problems and was facing bankruptcy. It became almost a racial epithet, often used by black tenants against white owners.

"Slumlord" has been in decreasing use since the 1970s.

(Oxford English Dictionary)
slum landlord, one who lets slum property to tenants, esp. one who allows his property to fall into disrepair; hence slum landlordism, the practice of letting slum property; slumlord U.S. = slum landlord above; hence slumlordship
1893 G. B. SHAW Widowers' Houses III. vii. 84 The worst slum landlord in London.
1953 Chicago Daily News 12 Sept. 3/7 Reporters..found that slumlords frequently twist Illinois' trust laws into blinds for escaping detection.
1957 N.Y. Times Mag. 12 May 36/3 The landlord had bitterly protested..that he was not a 'slumlord' and avowed that he was ready to put the building in condition if he could get a guarantee that it would stay that way.

7 February 1955, New York (NY) Times, pg. 14:
DEBT BAN URGED
ON "SLUMLORDS"
(...)
Chief Magistrate John M. Murtagh proposed yesterday that a city agency be empowered to chop the debt structure of run-down tenements and turn the properties over to "real" owners instead of "slumlords."