boiler up Share definition Flag To boiler up (also see, "boiler-up") means to take a hot, fat, steamy dump. After a night of drinking at the Upstairs, and a late night run to Taco Bell, Matt P. went home to boiler up. boiler up by Matt Painter November 20, 2007 0 0 Get merch Get the boiler up mug. Buy Now — $32.95 See more merch