a chink in armour

a chink in somebody's armour

(British & Australian) also a chink in somebody's armor (American & Australian)

if someone or something which seems to be strong has a chink in their armour, they have a small fault which may cause them problems She's a brilliant businesswoman, but her lack of political awareness may be the chink in her armour.

Common Names:

Name	Pronounced	Usage
Lisa	LEE-sə (English), LEE-zah (German), LEE-sah (Dutch)	English, German, Dutch, Swedish, Norwegian, Danish, Italian
Xanthippi	-	Greek
Athy	['æθi]
Tansy	TAN-zee	English (Rare)
David	DAY-vid (English), dah-VEED (Jewish, Spanish), da-VEED (French), DAH-vit (German, Dutch), DAH-vid (Swedish, Norwegian), dah-VEET (Russian)	English, Hebrew, French, Scottish, Spanish, Portuguese, German, Swedish, Norwegian, Danish, Dutch, C
Poseidon	pə-SIE-dən (English)	Greek Mythology