Double-Edged come from an ancient word meaning (pure rage). It would normally be used to describe something annoying or out of order. If someone is double-edged then they would be an annoying piece of shit and a waste of space.
Some use Double-edged as a good thing, this use of the world is completely wrong and these people are morons.
"Double-Edged Nettles!"
"Darragh you double-edged pedophile."