A blacksnapper is a person who mostly replies with a black photo with text on Snapchat. You send a beautiful selfie to them, and all you get back is a lousy blacksnap. A blacksnapper is a person who don't understand that snapchat is an app for sending photos, and that he/she rather could have sent a regular message instead of covering up the lens and blacksnapping.
Person 1: It's so boring to snap with John.
Person 2: Yeah, he always sends a black screen with text, never a selfie or anything.
Person 1: Yeah, he is a real blacksnapper
Any sort of situation* in which an awkward moment, usually created by a foul move on the part of one of the sexually interested, prevents an individual from having sexual relations with their "target" over the course of the night.
*including, but not limited to parties, tailgates, bonfires and thirsty thursdays
Skyler: So bro, it was totally going with this chick. She kept complimenting my flow and everything. Then, out of no where, my boy came up and iced me in front of my slam piece. She totally dipped!
Brad: Dude! You didn't get to sleep with her? Totally cock blockward!
Someone who only looks good from a block away, but when they get close you realize it was all an illusion. A variation on the ever popular butter face.