(From split <divided> + spiff <well-dresssed or good>)
a quality cigarette rolled with both tobacco and marajuana, initially popular on Europe's Iberian Peninsula
additionally, the term has been adopted to mean any high quality or well-rolled marajuana joint
"The party was wack 'til mah nigga busted out a FATTY spliff!"
Spliffs are traditionally rolled in the european cone style, but in general refers to the tobacco content more than particular form.
Note, this can be used as a verb whilst rolling to describe the act of adding tobacco, hence "spliff it".
"You should spliff it, this stuff is very good" or
"That spliff is a really fat cone, good job!"