Rapper Young Thug -- Thuggin' In Atlanta Jail Cell

Rapper Young Thug is living up to his name ... living the thug life in a jail cell ... after getting busted by Atlanta cops.

Law enforcement sources tell us ... Mr. Thug was pulled over Tuesday afternoon for reckless driving and what cops call "laying drags" -- driving in a circular or zig-zag motion. They also popped him for driving without a seat belt.

We're told ... when cops ran his license ... they found an outstanding warrant for drug possession and that's all she wrote.

YT is a hot new Atlanta rapper ... who says he just signed a big deal with Cash Money.