Obnoxnox
A person who thinks they're cool, but they're just a mess of bad choices and worse opinions.
My friend is obnoxnox. He thinks he's the best at everything, even though he failed math.
My coworker is obnoxnox. She interrupts everyone in meetings just to show off.
My brother is obnoxnox. He won't stop talking about his video game even though he's losing.