Achilles heel, Achilles tendon

Achilles was a great warrior who fought in the Trojan War on the side of the Greeks. When he was born, his mother discovered that his fate was to die in combat. She tried to make him impervious to weapons by dipping him in the sacred river Styx. In order to do that, she had to hold him by one heel, and that part didn't get wet. During combat on the fields of Troy, Paris, prince of Troy, shot an arrow at Achilles. The god Apollo guided it into the one place where Achilles could be hurt, his heel. He died. A person's "Achilles heel" is his or her ____?______ . strong point weak point confused point