When Achilles was born, his mother, Thetis, tried to make him immortal by dipping him in the river Styx. Therefore, the place where she held him remained untouched by the magic water of the Styx and that part stayed mortal or vulnerable. It's Greek to Me, tells us that Achilles didn't always have a vulnerable heel. Oh yes, he had a weak spot, but according to the original story about Achilles, Homer, in the Iliad , said it was his pride. Later versions indicate his weakness was his love for the Trojan princess Polyxena.
Many people get unlimited mileage out of a limited vocabulary.
When one word leads to another, it generally ends up in a quarrel, a speech, or a dictionary. E.C. McKenzie Native ability without education is like a tree without fruit.