chink in someone's armor
US /tʃɪŋk ɪn ˈsʌmwʌnz ˈɑːmər/
UK /tʃɪŋk ɪn ˈsʌmwʌnz ˈɑːmər/
1.
a weakness or vulnerability in someone or something that is otherwise strong or well-protected
:
•
The prosecutor found a chink in the defendant's armor during cross-examination.
•
Despite his confident exterior, there was a chink in his armor when it came to public speaking.