giga-nut Share definition Flag The act of climaxing and having a heart attack at the same time resulting in an otherworldly orgasm and a heart attack. I hereby sentence you to death by giga-nut. giga-nut by SpiderUnicornFly April 25, 2017 0 0 Get merch Get the giga-nut mug. Buy Now — $32.95 See more merch