Upknuck 

The single most positive affirmation between friends, colleagues, what have you. Said affirmation carries more weight than even those of normal knucks, secret hand shakes, high fives, etc. An Upknuck is preformed when two, or more, people bump fists with metacarpals facing toward other participant and phalanges facing up towards the sky. "Turn that pound upside down."

Rules to Upknuck:
1. You don't deny an Upknuck at any point one is offered. Said denial of Upknuck can result in said Upknucker refusing any further Upknuck related offers to said Upknuckee with Upknucker being completely justified.
2. You don't blow up an Upknuck. Ever.

Dude 1: "Just got a rim job from Sally!"
Bro 2: "Upknucks, brooooo!"

Upknuck by BradJacobGrose September 6, 2010

Upknucks 

similar to knuckles, but this action is with the knuckles facing up.. or (upside down kuckles)

upknucks brooo

Upknucks by j_walls July 30, 2010

Upknucking 

To violently give oral sex and ejaculate in a person's mouth, then uppercutting them so hard that the ejaculate flies out of their mouth.

"That date last night was so crazy, she asked if we could do some upknucking."

Upknucking by Claym0re March 7, 2025

Unknuckles 

When you're so fat that your knuckles have dimple inward instead of protruding predominantly outward

Did you see Sarah's Instagram post of her new manicure? She's gotten so fat all I could see is her unknuckles

Unknuckles by Mikey Sly February 9, 2021

Mofoin Ucknucker 

A greeting from one drunkard to another, essentially slang for mother fucker

What's up mofoin ucknucker, ltns!

Mofoin Ucknucker by Comequicksee March 8, 2023