It has been the Achilles heel for online retailers over the last couple of years. Many had items out of stock, or they were taking too long to deliver, or it was taking too long to shop.

All interesting heroes have an Achilles' heel.

We gave up a couple of long runs last week and it has been our Achilles' heel. Sometimes when we're too aggressive those long runs happen. I like the aggressive mistakes, but we have to cut down on those mistakes.

Anybody who has political ambition has an Achilles heel.

The Achilles Heel of the Americas was the lack of cultural confidence typical of new settlers.

That's been the Achilles heel of our team the whole year.