When you are drivin' with drugs in your car, specifically weed, pot, marajuana, in the car either hidden away in the glove box or out and blazed up in the driver seat.
Man, put that shit out, Don't let them catch us ridin' dirty.
Stop looking mad shady or thay'll know we ridin' dirty.
In the computer industry, the term "ridin' dirty" is used to describe a computer that's behaving erratically or running slowly due to excessive software and/or spyware on the system. Frequently, these systems must be rebooted or reinstalled.
It was taking my system like 10 minutes to boot up. Turns out it was ridin' dirty because when I removed some programs from the startup folder, it came up real quick.