Renting something you're already renting, like college roommatessplitting the rent, but only one's on the landowner's contract--the other is subletting
Suburbanite: Yeah, I was nervous he had a knife or something and was going to... SHANK him!
Suburbanite 2: Whoa. You're like, subhetto talking about shanking and stuff!
A subletter is someone who owns or rents a property and ends up subletting it, or letting someone else stay there and that person pays the rent to the subletter who then pays the rent to the landlord or bank, or whomever you report to to pay off your rent/mortgage.