Slart Share definition Flag A slimy or "slippery" fart. Often one of those symptoms associated with your common hangover or gassy and/or upset stomach. "OH...ummm... I uhh.. I SLARTed and I gotta go!!!... and sorry about your couch dude..." Slart by YouKnowWho2 March 10, 2008 0 0 Get merch Get the Slart mug. Buy Now — $32.95 See more merch