Abbreviation for Mac Daddy Lew, which is an alias for rapper Lewisville Slugga. Originates from girls back in high school who noticed he had lots of girls. Still is used in occasional songs.
Brandee: "Hey MDL! You got any green?"
Lewisville Slugga: "You got some head?"
Much Dinosaur Love. When two people of the opposite sex are good friends but not dating. They always act like goofs.
Guy 1: Are you dating her?
Guy 2: Nope we have MDL for each other