The new, latest evolution of the emo subculture. Characterised by the ritual mutilation of the scrotum with a knife. Ballcutters are seen as "hardcore" by their emo contemporaries, as they despise their 'masculinity' so much that they're willing to carve any remnant of it. Although the dangers of ballcutting are many (some of the more serious including sexual dysfunction and infertility), most Ballcutters seem to proceed obliviously, believing these issues pose no real issue to their current sex lives.
Emo Boy: Hey man, are you having your period?
Ballcutter: Dude I'm a guy. You gotta start going to Health class.
Emo Boy: Well why are you bleeding out of your crotch?
Ballcutter: Oh I'm a ballcutter.
Emo Boy: Huh?
Ballcutter: Yeah my parents fully don't understand me, and my teachers don't respect my individuality, so I decided the only way to express myself emotionally was to lacerate my scrotum.
Emo Boy: Wow man, that's deep. You gonna write some poetry about it?
Ballcutter: Pfft. Poetry is for fags. I'm going to take some pictures of my ballsack and stick them on Myspace.
Someone who either cancels plans at the last minute or just flat out bails and doesn't show up for a party etc.
If someone does this, it is said that they "CUT YOUR BALLS OFF." So a ballcutter is someone who cuts your balls off.
"Hey did Tanya show up at your party?"
"Nah, dude. She's a ballcutter."