Achilles' heel

Pronunciation pronunciation key
ăkileez

Definition 
A fatal weakness; a place where an otherwise strong person or thing is vulnerable. The allusion is to the legends surrounding the great Greek hero Achilles, who became virtually invulnerable after being dipped by his mother, Thetis, in the waters of the River Styx as a child. But in order to dip him, Thetis had to hold him by his heel, so this one area was not touched by the water and remained the one part of his body in which he could be wounded. Ultimately, Achilles met his death when he was shot in the heel by a poisoned arrow fired by Paris during the Trojan War. On the basis of the same legend, the fibrous cord that connects the heel to the muscles of the calf is known as the Achilles tendon. Her sense of vanity is her Achilles' heel, and all her enemies know it.