Achilles heel

or Achilles' heel

noun

1. a portion, spot, area, or the like, that is especially or solely vulnerable:

   His Achilles heel is his quick temper.

Achilles heel

noun

1. a small but fatal weakness

Achilles' heel

1. A point of vulnerability. ( See Achilles .)

Word History and Origins

Origin of Achilles heel¹

First recorded in 1800–10

Idioms and Phrases

A fatal weakness, a vulnerable area, as in This division, which is rarely profitable, is the company's Achilles' heel . The term alludes to the Greek legend about the heroic warrior Achilles whose mother tried to make him immortal by holding the infant by his heel and dipping him into the River Styx. Eventually he was killed by an arrow shot into his undipped heel. [c. 1800]

Example Sentences

Trump will be taking office having inherited an American economy that has performed very well, despite the discontent voiced among many voters who may have been the Achilles’ heel of Vice President Kamala Harris’ candidacy.

From Los Angeles Times

The fighting mentality has been Napoli’s Achilles heel for several years.

From BBC

Before Singapore, you might have said that street circuits were Red Bull's Achilles heel, which would have led one to believe Las Vegas might be an issue for Verstappen.

From BBC

And this will potentially be its Achilles’ heel.

From BBC

That deft sidestepping of the Trump attack worked because it exposed the vulnerability inherent in Trump’s psychological makeup, the narcissist’s one Achilles’ heel: Narcissists cannot tolerate being ignored.

From Slate