kacknerd
A kacknerd is a person who thinks they're smart but is actually just loud and dumb. They're like a donkey wearing a crown.
My history teacher is a kacknerd. She said the Roman Empire was run by donkeys and that's why it fell.
My friend's dad is a kacknerd. He told the whole restaurant he invented pizza, but it was just a deep-dish cheeseburger.
The guy at the gym is a kacknerd. He said he can lift 1000 pounds but couldn't lift a bag of groceries.