àm-bé暗碼

secret code

secret code; secret signs used by a store to indicate the actual value of a commodity which is not known to outsiders

English Wiktionary, “暗碼” (CC BY-SA 4.0) — https://en.wiktionary.org/wiki/%E6%9A%97%E7%A2%BC · confidence: Medium (Wiktionary, Hokkien)