An Achilles' heel is a weakness in spite of overall strength, which can lead to downfall. It is rooted in the myth of Achilles' mother dipping him in the River Styx, making his entire body invulnerable except for the part of his foot where she held him the proverbial Achilles heel.

The concept of an Achilles' heel, derived from Greek mythology, symbolizes a vulnerability or weakness despite one's overall strength or prowess. According to the myth, Achilles, the legendary Greek hero of the Trojan War, was rendered invulnerable by his mother, Thetis, who dipped him in the River Styx. However, she held him by the heel, leaving that small portion of his body unprotected—the proverbial Achilles' heel.

This mythological tale has transcended its origins to become a widely recognized metaphor for human frailty and vulnerability. In various contexts, an Achilles' heel represents a critical weakness or flaw that, despite an individual's strengths or accomplishments, can ultimately lead to their downfall or failure.

Throughout history, the concept of an Achilles' heel has found resonance in literature, psychology, and popular culture. It serves as a reminder that even the most formidable individuals or entities are not immune to vulnerability, and that awareness of one's weaknesses is crucial for personal growth and resilience.

In contemporary usage, the term "Achilles' heel" is applied metaphorically to describe any area of susceptibility or vulnerability, whether in individuals, organizations, systems, or strategies. By recognizing and addressing these weaknesses, individuals and entities can mitigate risks and enhance their chances of success and longevity.