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.
Randy was a cockblock because he told Jaime that this guy she knew was just using her for sex.
By Liz
Cockblock
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 person who comes between you and a successful score by continually derailing the train or showing up at the worst times possible with inane, unrelated blather
Got cockblocked by mom last night. Amy said she was ready to go all the way, but she went home instead and I got grounded. I might be a virgin for another week yet.
John was about to go home with some hot blonde until her fat friend cockblocked him and went home with her instead to eat candy bars and watch the Tyra Banks show