pàng-khang-siâⁿ放空城

to present a bold front to conceal a weak

to present a bold front to conceal a weak defense

English Wiktionary, “放空城” (CC BY-SA 4.0) — https://en.wiktionary.org/wiki/%E6%94%BE%E7%A9%BA%E5%9F%8E · confidence: Medium (Wiktionary)