What is the meaning of an Achilles' heel?

An Achilles' heel refers to a person's or organization's specific point of weakness or vulnerability, even if they are otherwise strong or successful.

Why is it called an Achilles' heel?

The term comes from the Greek myth of Achilles. His mother, Thetis, dipped him in the River Styx to make him invulnerable, but she held him by his heel. Because his heel never touched the water, it remained his only vulnerable spot.

Who first used the idiom 'Achilles' heel' in English?

While the myth is ancient, the earliest known use of the specific English idiom in print dates to 1810, used by the poet Samuel Taylor Coleridge.

Achilles Heel Meaning | Idioms Online

An Achilles heel is a person’s (organization, country, etc.) weakness or vulnerability. Although it can refer to a physical weakness or limitation, this idiom can also refer to any perceived weakness, including psychological. It may also refer to someone successful, strong, or otherwise doing well, but who has one ‘fatal flaw’ or weakness that could bring about their failure or downfall. The weakness or flaw doesn’t necessarily have to be negative, in general.

This idiom is used in jest as much as it is used seriously. For instance, a person might say, “Ice cream is my Achilles heel,” even though they have no intention of saying that ice cream will be their ‘downfall.’

Sentence Examples

“The mayor’s womanizing was his Achilles heel.”

“The team had an Achilles heel, their inexperienced outfielder.”

“Martin’s selflessness proved to be his Achilles heel.”

“Gambling was his Achilles heel.”

“He’s too good a fighter. He has no weaknesses.” “Everyone has an Achilles heel. We just have to find his.”

“Everybody has got an Achilles’ heel, and I make a point in remembering my associates’ ones.” — Filth (2013)

“Last night at the bank, I noticed something about Two-Face.” “His coin.” “It’s his Achilles heel. It can be exploited.” — Batman Forever (1995)

The Achilles Heel Legend

This idiom comes from Greek mythology. Achilles was a great Greek warrior who was invulnerable in battle, or almost. He was the son of the Nymph, Thetis.

Thetis was married to Peleus. According to some stories, this marriage was unhappy and against her will. Since Peleus was a mortal, this meant Achilles was only semi-divine. As if this wasn’t bad enough, when Achilles was still an infant, Thetis became aware that Achilles was destined to die early at Troy. She hatched a plan to keep him alive.

Achilles’ Fatal Flaw

In one of many stories, Thetis took Achilles to the River Styx and dipped him in the waters. The waters made Achilles invulnerable and gave him great strength. However, to dip him in the water, Thetis held him by his heel. Therefore, his heel did not get wet and was not made invulnerable like the rest of his body. This became his one weak spot.

In truth, the river dipping was only one of many attempts by Thetis to prevent her Son’s early death. But his heel became his downfall during the Trojan War. Paris, the Prince of Troy, fired an arrow through his heel, his one vulnerable spot, which killed him.

Note that this story is a later addition to the Achilles legends. He was not invulnerable in all stories.

Achilles not only lent his name to an idiom but to a part of the human anatomy. The Achilles tendon is the very prominent and tough band of tissue that connects the heel bone (calcaneus) to the calf muscles. Just as it was for Achilles, this area is vulnerable for all of us, as many people suffer a rupture of this tendon during sports activities or exercise, especially after the age of 30.

Homer vs. the River Styx

It is a common misconception that Achilles was always considered invulnerable. In the earliest and most famous account of the Trojan War, Homer’s Iliad, Achilles is a mortal hero who can be wounded like any other man. In fact, Homer describes him being injured in battle and bleeding.

The story of his mother dipping him into the River Styx to make him immortal was a much later addition to the mythology, first appearing in the writings of the Roman poet Statius around the 1st Century A.D. This “later” version of the story is what gave rise to the idea of the vulnerable heel, and eventually, the idiom we use today.

Origin of the Idiom

While the legend of Achilles is thousands of years old, the specific English idiom “Achilles’ heel” is a much more recent addition to our language. For centuries, writers referred to the story of Achilles as a literal myth, but they didn’t use it as a standalone metaphor for a “single point of failure.”

The earliest known use in print of the idiom is attributed to the poet Samuel Taylor Coleridge in 1810. In an essay, he wrote: “There is a part of the person which is not immortal… the Achilles’ heel of the most invulnerable.” This is a perfect example of how a writer takes an ancient concept and finally gives it a specific English “label” that we still use today.

**The Mortal Version: Achilles in the Movie Troy (2004)**

Modern audiences are often most familiar with the story through the 2004 film Troy, which takes what is known as a Euhemerist approach. This is the practice of interpreting myths as accounts of actual historical events, grounded in reality, that were later exaggerated and mythologized.

In the film, Brad Pitt’s Achilles is not an invulnerable demigod. There is no mention of the River Styx or magical protection; he is simply a peerless mortal warrior. When Paris eventually strikes him in the heel with an arrow, it isn’t a “magical” fatal blow. Instead, the injury hobbles him and prevents him from defending himself, allowing Paris to finish him off with several more arrows to the chest.

This version highlights the literal meaning of the idiom: even the most powerful person can be brought down by a single, well-placed vulnerability. By removing the magic, the film shows how a real-world battlefield injury could be transformed over centuries into the “fatal flaw” legend we know today.

While Achilles’ story is one of a single point of failure, other Greek myths focus on different types of struggle, such as the Sisyphean Task, which describes labor that is endless and entirely futile.