a mean person
A mean person is a f***ing waste of oxygen. They need to put others down just to feel good about themselves. They're the kind of person who calls you names and throws s#!*% at you like it's a party.
Your teacher called you a f***ing idiot because you didn't do your homework. Then she threw a paper airplane at you.
Your friend's mom called your friend a f***ing loser because she didn't clean her room.
Your brother threw a bowl of soup at you because you said he looked like a f***ing rat.