Mark of the Unclean 

A visible stamp on your hand the morning after a night out drinking.

Many bars that charge a cover will stamp people's hands before they go in so they know who has already paid. When the stamp a person received is still visible the day after, that indicates the person has not showered. Thus they bear the mark of the unclean.

Susie wanted to hook up with Tom in the morning, until she noticed he bore the mark of the unclean.

Mark of the Unclean by thendcomes June 12, 2012

Unclean Toothpaste

The act of a man having sexual intercourse with a woman, ejaculating onto a toothbrush, and making the woman brush her teeth with it.

Yo I had sex with this hot chick last night, but her teeth were in terrible condition. So I made her brush her teeth with Unclean Toothpaste.

Unclean Toothpaste by yeayea friedman February 21, 2011

unleaded

Decaffeinated coffee. Crap that tastes like coffee but doesn't give you a caffeine buzz. Waste of time...

Waitress: What can I get you?
Customer: Coffee..
Waitress: Leaded or unleaded?

unleaded by Hackermom December 10, 2005

unclean 

A sick, disgusting person.

He is such an unclean

unclean by anonymous March 12, 2003

doctrine of unclean hands

Legal doctrine describing the absolute wrongness of setting your Starbucks down on the urinal while you drain the weasel. By your act, the coffee is forever unclean, and any attempt to rationalize it that it was just the bottom of the coffee cup that touched the urinal is futile. Osmosis by grossness occurs, and you are basically drinking other dudes' urine.

One of the essays on the bar exam last year involved the doctrine of unclean hands.

doctrine of unclean hands by Ae5Ea8 March 27, 2015

Unleaded

Hangin out with your homies without your girlfriend, wife, or any assorted bitches that you might be seeing.

Derived from the gasoline terminology leaded and unleaded, as well as the fact that when you're hangin out with your girlfriend, bitch, or wife your weighed down, thus you're leaded with the ball and chain.

We goin out tonight?

Yea, we're rollin unleaded so leave da wife at home.

Unleaded by ArtyArt November 10, 2005

Premium Unleaded 

Giving a girl 'Premium Unleaded' is when you are fucking a girl up her stupid ass, and you start pissing uncontrollably. USUALLY used as a method of revenge, e.g. during breakup sex

-While we were fucking for the last time, I made sure to give that cunt some Premium Unleaded.
-She squeal like the little bitch she is?
You fucking know it, revenge is the shit man.

Premium Unleaded by TupaC FoR pREs April 13, 2004