To have a moment or point in your life when you are considered an idiot. A.K.A. dumb ass. Comes from the 2 terms knuckle head, and dumb shit.
1. I can't believe you didn't shift out of first gear after proceeding 100 miles an hour, you're a knuckle shit!
2. Josh-"Did you guys drill the hole out for the waterfall bolts on tower 13 yet?"
Bobert-"No, not yet."
Josh-"Well, now you've gotta go drill that hole out even though I told Randy I would do it, you fuckin' knuckle shit!"
Its when you wipe your ass after a particularly filthydump and you get a shit stain your thumb knuckle.
I was pleased to finally get the key to the executive wash room, however Stan Phillips was not pleases to see that I had a shit stained thumb knuckle when I shook his hand at the share holder meeting.
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."