Similar to cop blocking, only more specific. An interference, that brings a hault to any sexual act involving a man's (or a woman's in some cases) penis. It is sometimes used even when a man (or a woman with a penis) is just talking to someone, this is a stretch but is appropriate as long as their intentions are to eventually have sex with the person they are talking to, and they have some chance. If the person they are talking to shows no interest, and one interrupts...then they are probably doing this person a favor. Either that or just adding insult to injury.
Yo we was kissin, she had her panties off and her hands all on my dick, I was just about to smash...>sigh< until John cock blockin ass "accidentally" walked in on us.
by FooGe March 26, 2004
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Something that should be a illegal.
An act of stopping someone from getting laid.
You're like a giant... cock blocking robot, like developed in a secret fucking government lab.
by FUCKWE'REALLDEAD September 11, 2010
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to keep a brother from getting laid with your pressence
johns little brother cock blocked him by not leaving the room.
by M&M October 23, 2003
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A dangerous impedement to getting pussy which can rear it's ugly head in many different forms and situations. To categorize a few...

1) The Third Wheel - A friend of the chick you are trying to get who doesn't want to leave her side, and will not until your target says otherwise.

2) The Lame Duck - When trying to get a slutty girl, a lame duck may be another individual who knows the sluts reputation, and is hanging around her, but is either bogged down in their efforts to spit game, or downright wasting her and your time by not getting any, but instead keeping the slut company.

3) Rich People - Sometimes at a party, those ridiculously rich white kids come down, and since most girls are attracted to money, they start hanging around them. Of course, most rich people who come down to urban parties are there for a bigger reason... to do oxycontin, cocaine, and other garbage and get our females hooked onto it. Definately one of the worst.

4) The Ex - If your potential mate has an Ex-Boyfriend somewhere in the premises, things can get ugly if he's the hothead type. Thankfully, I'm a Marine and could careless about a civilian, but for other people who aren't deadly weapons by law, just keep your eyes out, these morons can not only cock block your entire operation but can get the jump off blown up too.

5) Accidents - Sometimes even your closest buddy might let something stupid slip, like that time you had that threesome with your potential mate's sister. Or it might be a cock blocker letting it slip intentionally. Me and my clique follow a strong code of silence on matters like this, but when it comes to getting the finest bitches, trust can fall like a house of cards in a hurricane.

There are many more you might have the misfortunate of encountering. Just keep smooth casanova and you can sometimes blitz right past them and go straight for it. After that, all you need to worry about is not getting burned.
1) I wanted to talk to that girl alone, but her bitch friend kept hanging around us being a third wheel cock block.

2) That dude keeps trying to holler at that slut but isn't getting any, and I'm the one who called her to come here and give me brains in the first place.

3) I was hollering at this chick when these random white dudes from the sticks came. Next thing I knew, the chick was strung out on coke.

4) I was fingering this chick in the back, when her ex comes in and starts wiling out.

5) I was spitting mad game at this chick, when my drunk ass friend comes over and says "Isn't her sister the girl we gave the goggles too that night?"
by The Sub January 10, 2005
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1.) To interfere with someone who is getting acquainted with, conversing with, or hooking up with a member of the opposite sex

2.) A motor vehicle maneuver, usually done by insecure twenty-something males (who think that everybody wants to race them) and other ignorant people, designed to prevent someone from changing lanes in traffic
1.) At the club, Sal was was about to get Lisa's phone number, when Nathan came up cock-blocked him by asking him if he found a job yet. He made it even worse when he reminded Sal that they had to hurry up and catch the last bus home. Lisa rolled her eyes and walked away.

2.) I realized that my exit was coming up so I began to change lanes, but that ricer cock-blocked me

3.) The traffic on the highway was hell, mostly because of that soccer mom driving the minivan in the far left lane, pacing and matching speeds with the semi in the middle lane. She cock-blocked us all.
by TheGrandInquisitor January 25, 2005
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Someone who uses different strategies to keep others from having sex
1. Courtney announces to others that a guy has herpes so even though eveyone gets a good laugh, no one will touch him.
2. Trashley: "Courtney is a natural-born cock-block because she falls asleep in the room everytime I want to bring my boyfriend in there!"
by maddox08 September 27, 2005
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Cock block a guy messing things up for another guy with a girl because he's likes her
My so called friend lee cock blocked me the other day. he really messed things up with Emma just because he likes her too
by 35cat27 November 19, 2013
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