Stands for "Slow, loud and bangin'". Can be used as a descriptive adjective, or as a noun to refer to a car that is fully loaded with rims, tint, hydrolics, etc.
PART(S) OF SPEECH:
Cuz' I love it, thereeeee's nothin' wrooong
With T comin' thrroouugghh, baby not at aaaalllll
Heeey, droppin' my slab with me and you can never go wrong
Cuz' my slab is true, ooh baby
--Lil' Flip, "Candy on Chrome"