A failed attempt at explanation that leaves you more confused than you were before.
I thought I had deduced what was going on in that opera; but now after sitting through your long-winded vexplanation I have no idea why it ended as it did.
Someone who's not very smart but goes on talking and talking circuitously around a subject without ever making any coherent point. Could be used to describe many politicians, including several State of the Union addresses of the past decade. Also applies to university professors, conference speakers, TV and radio personalities, etc.
"I can't believe so many people voted for that meanderthal."
"How did this meanderthal ever get tenure?"
"I actually paid money to sit here and listen to this meanderthal?"
"Enough of this meanderthal! I'm changing the channel."