gackaholic Share definition Flag someone that does alot of crystalmeth. from the words "gacked" and "alcoholic". to be said as a joke to someone. you get on one everyday, you damm gackaholic. gackaholic by S. 22nd street October 20, 2006 0 0 Get merch Get the gackaholic mug. Buy Now — $32.95 See more merch