1.To Cock Block your friend from talking to or fucking a girl.
2. Preventing someone from getting in a girls pants.
You are at a bar talking to a girl and your friend jumps between the two of you and starts talking to her.

Girls can C-Block guys too by preventing them from getting in their girlfriend pants. Usually by making them leave with them instead of you.

by Notorious JRB June 21, 2006
Also know as Cock-block. Commonly found at Fraternity party. Person A is talking to hot drunk chick, when his friend Person B comes up, equally as drunk and embarasses person A, to the point where drunk hot chick no longer wants to give up the buns.
"Dude, you cheesehead bastard. Why are u bringing up my sexual ineptitude in public?!? I could have SCORED!"
by CoorsLightEMU April 20, 2003
Dude, I was hitting on this chick and he c blocked me by showing off his Mercedes. Now she won't talk to me.
by Gavin So Complicated August 17, 2006
the area in which all the BOOOOOOYS hang out at school, bunch of good cunts there, brotherhood.
Sanjay: you going to kick it at C BLOCK today at lunch bro?
Gulas: of course!
by bartyboy June 3, 2011
the area of Glen Ridge that is within a blocks distance of carteret park. basically where all the bros live
c block is where all the bros chill
by ChloePowell April 26, 2011