assmason Share definition Flag One who specializes in assmasonry. see: asshat, dipshit, moron, idiot, etc. "God dammit, Chris is such a fucking assmason." "I don't wanna hear it, assmason." assmason by GARY LOVES THE BACON May 12, 2004 0 0 Get merch Get the assmason mug. Buy Now — $32.95 See more merch