A term the extends far beyond the meaning of "creeper." It is used to describe a creep to the ultimate extreme. Not your typical creeper. A true professional creeper that could put all the other creepers to shame. Be very careful around these types!
Dude, that kid was a total grist -- he was staring at the shower stall as I was coming out.
Don't be a grist! Being in the same class does not give you permission to trail me there from less than two feet behind me.
That was gristy man... looking through my facebook pictures with one hand in your pants... and then reducing the screen and acting like nothing happened as soon as I walked by. That's beyond creepy; it's just downright gristy!
Don't get too drunk at this party man; I think we may have a grist here -- so unless you want to wake up with an enlarged anus, keep the booze to a minimum.