Origin of Phrases - C
Chink in the armor
Meaning: To have flaw or problem preventing success.
Example: This plan about retiring early has just one chink in the armor, we have no money.
Origin: "Chink" is an obscure word meaning a slit, fissure, or weak spot that can leave one vulnerable.
Hence "Chink in the armor" means a weak spot in ones protection or plan.