black rent

noun2

1. •
   (old-fashioned) Blackmail (rent paid in corn, meat, or the lowest coin).

   • [F]rom whose rich domains in Meath he received a “black rent” equivalent to £10,000 a year[.] — 1856
2. •
   (Ireland, historical) Protection money.

   • [S]he pays me the black rent, and I let her alone[.] — 1831