A spliff is an old school term originally referring to any joint where you might have to "split the difference" between tobacco and cannabis. It can be flower or hash that is mixed with tobacco. Maybe it's because you only want to smoke a little bit of weed, but don't want to roll a pinner, or because you only have a little bit of weed, and don't want to roller a pinner. As the term became popular, and the availability of weed became greater, the term began to incorrectly refer to pretty much any type of joint, with a crutch or not, cone or not.
"Man, you got a smoke we break open for a spliff? I've only got papers, but don't want to smoke all my weed in a joint. "

"No, but I got a Philly, if you wanna roll a blunt!"

"Man, I said I didn't wanna smoke all my weed at once...but hell yeah! Let's get blunted!"
by bean, trivia queen January 7, 2015
a cannabis cigarette.
cannabis.

"good spliff demands good food"
George: That spliff has given me the major munchies.

Greg: Spliff's are a mans best friend... Sorry i'm stoned!
by CannabisKings April 3, 2019
the ability to quickly roll a spliff.
your quickness is directly related to your spliffness.
Maggie: Wow Greg, your spliffness is amazing!
Greg: Listen Struggles, my spliffness is no match for yours!!
by RyanGregMaggie May 19, 2010
also splif

(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
"I don't have much weed left, but I can roll us both a spliff."
OR
"The party was wack 'til mah nigga busted out a FATTY spliff!"
by Johann7 August 24, 2004
A joint (marijuana cigarette)sometimes rolled with half weed, half tobaco, or sprinkled along the bud.
Smoke a big spliff with some good sensimillia
by J-Dawg November 8, 2003
A self-rolled cigarette containing a combination of marijuana and tobacco.
Roll me a spliff and let's get wrecked!
by T-High December 20, 2008
A joint rolled with tobacco in it. Often spliffs use a high ratio of marijuana to tobacco, but when hash is used or marijuana is of high quality (See Headies), this ratio can be decreased to conserve.

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".
"We should roll a nice spliff and go for a drive" or
"You should spliff it, this stuff is very good" or
"That spliff is a really fat cone, good job!"
by Matt VH August 11, 2007