A greebo is a person who usually lives in a rural small city in the midwest or someplace in canada or alaska. They follow mainstream metal and hard rock bands like Marlyn Manson or Slipknot. They buy those baggy fake bondage pants from hottopic.
But just because they don't know anything about real metal or punk rock, don't let that fool you, they're still hardcore as hell, they're just ignorant to boot. They tend to live in trailor parks or indian reservations and have mothers who are probably meth addicts or alcoholics.
They usually don't complete high-school and are charged with a variety of domestic violence crimes. They do plenty of drugs, and talk about it freely.
The reason why they dont know about the more obscure bands is because simply they haven't been exposed to any real 'scene' living in their rural community.
Tom was a goddamn greebo asshole with a face full of zits and long black hair. Spent all his time smoking ciggarettes in the highschool parking lot trying to sell meth, even though he dropped out 2 years ago. And he always wears the same goddamn Rob Zombie T-Shirt. I hear he also had sex with his cousin, but what else to expect in Alaska.