Knee Clapper 

A rash looking STD you get when rubbing a mans penis inside the bend of someones knee.

1. Did you hear Joe gave Jamie the knee clapper on the church trip

2. My parents are going to kill me if they find out I have the knee clapper

Knee Clapper by 2 girls half a brain September 26, 2013

Knee-clapper 

When a prism claps their knees when they walk.

James Horton is a knee-clapper when walking the halls of Cranston West

Knee-clapper by MclovinDATa$$ May 30, 2018

knee capper 

A guy with a penis that hangs to his knee

That dude right there has a knee capper (see the grey sweatpants)

knee capper by Jay bone Capone July 8, 2024

kneeslapper 

When one finds something extremely amusing, while seated the person slaps their own knee in jubilation.

That joke was a hellava kneeslapper, I laughed my ass off.

kneeslapper by Count Funkula June 13, 2003

Kneeslapper 

The most extravagant reaction to something of funny, or toast-worthy nature, where someone uses their hand to make contact with their knee typically in a very absurd and flamboyant manner.

Guy: hey guess what
Guy#2: what?
Guy: UR MOM
Guy: performs a kneeslapper

Kneeslapper by Toastingurmom May 8, 2018

kneeslapper 

Someone with a dick so big it slaps there knees while walking.

When ol boy pulled his kneeslapper out; she knew she was going to be walking with a limp the next day..

kneeslapper by lilsmarterthanaboxofrocks March 25, 2021

Kneecapper 

A person who loves to bust kneecaps.

Have you heard of what the Kneecapper did in D&D? It's insane!

Kneecapper by Karma Dragon June 9, 2019