achilles heel
[noun]
Synonyms: soft spot

[TahlilGaran] English Synonym Dictionary ▲

A·chil·les' heel /əˌkɪliːz ˈhiːl/ noun [countable]
[Date: 1800-1900; Origin: From the story that the ancient Greek hero Achilles was dipped as a baby into the river Styx to protect him, but the part of his heel he was held by did not get wet, and so remained unprotected]
a weak part of someone’s character, which could cause them to fail at something:
I think Frank’s vanity is his Achilles' heel.

[TahlilGaran] Dictionary of Contemporary English ▲

Achilles' heel
• Achilles' heel (of someone or something)
the weak part of a person/place/system/argument which can easily be attacked or criticized
The lack of skilled workers was the Achilles' heel of the government's plans to prepare for the Olympics.

[TahlilGaran] English Idioms Dictionary ▲

achilles' heel
n. phr., literary A physical or psychological weakness named after the Greek hero Achilles who was invulnerable except for a spot on his heel.
John's Achilles' heel is his lack of talent with numbers and math.

[TahlilGaran] English Idioms Dictionary ▲