Mold sack Share definition Flag An ugly piece of crap, or someone worthless to yours or anyone else's life, and they smell and look like piece of moist moldy dump Tony Francin, just leave, everyone hates you plus you are a Mold Sack Mold sack by Primetime#1 June 5, 2010 0 0 Get merch Get the Mold sack mug. Buy Now — $32.95 See more merch