Wail Share definition Flag 1. To engage relentlessly in any activity. i.e. having sex, eating, smoking, drinking, working. Indulgence. Damn, I'm about to wail on that girl. or Let me wail on that cigarette. Wail by sweetpotato August 12, 2004 0 0 Get merch Get the Wail mug. Buy Now — $32.95 See more merch