n. A surprisingly sadistic and brutal person in a position of power
The act of taking a surprisingly painful and brutal shit
"But sir, I need the leave of absence for a life-saving operation! You can't be a hillman on this!"
"Hey, I'm going to be late... I've been taking this hillman for like 40 minutes now."
A hillman is always unexpected, and will always shock you by just how bad it is for no apparent reason.