Fivehead is typically used as in insult towards someone-- usually if they do something stupid. It may also be the equivalent of "big brain," depending on the context.
"I cannot believe you exposed the imposters to the team! You are SUCH a fivehead."
"We won the round with our 500 Iq! I'm a fivehead."
"We won the round with our 500 Iq! I'm a fivehead."
by November Storm September 21, 2020