The Collaborative International Dictionary
Blunderhead
Blunderhead \Blun"der*head`\, n. [Blunder + head.] A stupid, blundering fellow.
Wiktionary
blunderhead
n. Someone who habitually makes mistakes or blunders
Usage examples of "blunderhead".
You were absolutely right, and I was a blunderhead not to consider other options.
Unlike you blunderheads, I would pass the trials and become a member of the Brotherhood.
Meanwhile he had his half-dozen blunderheads to coach, Bullard among them, and perhaps no one was more surprised than Bullard when he discovered that the little man could coerce and persuade.