1. To prevent a male friend or associate from getting some action.

2. Any such attempt to prevent a male friend or associate from getting some action.

a person who interferes with one's sexual intentions with another person

1.The act of obstructing one person's advances towards another.
2.A situation that obstructs; an obstacle
3.An act of ill etiquette in which a male is speaking to one female in a group of females, and the alpha female creates a disruptive environment.

1. To interfere with a man's attempts to seduce a woman.

2. abbr. Cockblocker(n.)

When you are attempting to get close to a girl and your buddy won't leave the room or starts telling less than flattering stories of you that cause you to lose an opportunity with your new female acquaintance.

To fully understand the ways of a clockblock, one must set a scenario. Ok, say you've been out all night hanging with this girl, and can sense that you are mere seconds away from going upstairs too hook up with her. Here comes your good buddy cockblock. His drunk, attention-needing self jumps right into the picture and tells your woman how beautiful she is, then throws up all over her. Instead of giving you a quality BJ, she drives old Cockblock home, leaving you by your lonesome to jerk off all night.

A device used by fat girls to prevent their hot friends from going home with you.