A word used to describe something that is both "sick" (amazing) and "chilling" (relaxed). Synonomous with "epic" and "legendary" although with a somewhat more relaxed connotaion.
john:whats up nigga
jamie:nothin g-unit, im fuckin illin with a mack 10 and a 4 pound blunt, represent.
By Sibel
Illin
Partaking in an activity which authorities would class as being no good. Range of illin activies are numerous and cover a wide spectrum of "offences" from loitering to smoking an L or casing a joint.