V. The act of stopping a guy from getting in a girls pants. (2) A dick move used by only the lowest of guys, and these guys should never be a "wingman" at parties or clubs.
Example 1. Jack and Jill went to the party to do the hanky panky, but little Franky is Cock Blocking Jack, and now jack will be in jail cuz he's about to murder Fanky.
Example 2. What Seth did to James in the Interview.