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

"Just like phyllo dough flakes apart, composite layers can peel apart because this interlaminar region is the Achilles' heel of composites," says Brian Wardle, professor of aeronautics and astronautics at MIT.

From Science Daily

"Resistance development is often the Achilles' heel of new antibiotics," said Prof Bazan.

From Science Daily

What is often an Achilles' heel for Labour they now hope is a strength, not least because they think many, many people feel worse off under the Conservatives.

From BBC

Campaign professionals understand that this Never Trump faction is his Achilles' heel but his people are committed to "let Trump be Trump" — mostly because they have no choice.

From Salon

However, Li and Cravatt's team showed that small molecules could be harnessed to target this "Achilles' heel" of cancer cells.

From Science Daily