Achilles heel uh-KIL-eez heel noun WS #1

a person's or thing's principal weakness or vulnerable point, despite overall strength

1. Despite his incredible intelligence, public speaking remains his Achilles heel.
2. Her lack of self-confidence has always been her Achilles heel.
3. Poor time management is the team's Achilles heel in competitions.
4. The company's Achilles heel was its outdated technology infrastructure.
5. His tendency to procrastinate is his Achilles heel in academic settings.