One who possesses the ability to clog someone's toilet
to the point of OVERFLOW (not merely backup
or slow flush) causing shitty water to cover the entire tile floor and parts of the adjacent hallway carpeting. This is not intentional, and happens despite multiple courtesy flushes throughout
the act leading to the final shitmastering
Dave: (Running out of the bathroom) Where's your mop bro?
Me: What? Why?
Dave: Your toilet's overflowing man. Shit is literally EVERYWHERE!
Me: You're the fucking
shitmaster dude... mad props. Now go clean