2. I was about to take her home, and then you had to make the remark about the old cheeseburger under the seat in my car, you damn cockblocker!
2. An ugly girl who comes out with her cute girlfriend(s) and prevents the cute girls from getting any game.
3. "Girls' night out." This is a cockblocker by virtue of its name and implications. There will inevitably be a girl or two in this group who are man-haters. They will brainwash their cute girlfriends into thinking men are bad, players, jerks. They will convince their cute girlfriends that girls need to stick together, no men tonight.
2. Cody: Hey Trevor, that girl is cute. Will you be my wingman and distract her ugly friend while I go talk to her? Trevor: No way dude, her friend is hideous!
In this situation, the ugly girlfriend is cockblocking her cute girlfriend.
3. Jessica: It's girl's night out! Yayyy no guys tonight! Ok girls, remember, we gotta stick together. Don't get sucked into any man-traps!
Person 2: Mmm... probably but I just smashed him yesterday, sorry.
Person 1: Oh my gosh, you knew I liked him! You're such a cockblocker!!