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
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.