kacap
It comes from the Turkish word for someone who cuts up meat. Russians used to be called this because they were total meat cutters during wars. Everyone hated them for it.
"You're a kacap! You killed my grandpa!", A kid screaming at a soldier in a history class.
"Kacap? That's the worst thing you could call me!", A guy on a video game chat.
"My teacher called me a kacap because I didn't finish my homework.", A student's DM to his friend.