factshit
When you know you're right and your enemy is wrong and they yell nonsense at you and you throw the worst insults back at them.
You say, 'I'm right, and you're a dumbass.' They yell, 'You're a factshit!' You reply, 'You're a factshit and a f***ing idiot.'
During a debate, your friend says, 'You're full of factshit!' You say, 'You're full of factshit and f***ing lies.'
Your mom says, 'You're being a factshit again!' You say, 'You're a factshit and I'm the only one who knows it.'