to interfere with a man trying to pick up a girl.
((Mike is Hitting on a Girl as Bobby Yells Across The Room))
Bobby : "Hey Mike did you get your herpes medicine yet?"
Mike : "Man, why you always tryna cock block me?!"
by xxcHoLa May 24, 2006
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n. one who interrupts an act of sexual intimacy, such as hooking up or having sex, by opening doors, calling phones, etc.

Can also be used in the verb form, "cock blocking"
Yo, homie -- close the door! Why you cock blockin`? Can't you see we're in the middle of sumthin?
by TE AM0 July 26, 2005
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A rare and unfortunate phallic affliction where a man is born with a rectangular, block-like penis.
Jane: "What the hell is that? Is that a Colgate box?"
John: "It's...my penis. I have cock block..."
Jane: "Um...ok. Well, this is gonna cost $90."
by duminik November 18, 2010
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When you are denied or blocked from sexual activity or arousal
Bertha's brother came home early, what a cock block.

Rita's Dad stayed in the same room watching TV with us, he is such a cock blocker.

The girl next door closed her blinds before she start to change, what a cock block.
by RuneX December 3, 2003
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Spicy Ray cock blocked me by telling the bitch I was married with two kids at home.
by Boogie February 14, 2004
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A cock block is when two males are moving in the same girl and the fellow with no chance prevents the second male from advancing on the girl. He cock blocked the second guy and both lose.
This scenerio involves a male "friend" of a girl who continually tries to break the friend boundry while another male moves in on the girl. When the "friend" refuses to let the new guy and the girl be alone, he is cock blocking him. In a way, he is throwing the game for both teams, since no one wins... a cock blocker!
by Penguin September 7, 2003
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When someone or something gets in the way of or messes up intentions of performing sexual acts involving your cock.

(From Super Bad)
Me: I was so close, but he totally just cock blocked me.
by tcady123 August 13, 2008
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