固ㄍㄨˋ若ㄖㄨㄛˋ金ㄐㄧㄣ湯ㄊㄤgùruòjīntāng

简固若金汤

  1. 形容城池或陣地非常堅固，難以攻破（金：指金城，金屬鑄造的城牆；湯：指湯池，蓄有沸水的護城河）​。例 「這座碉堡固若金湯，易守難攻」。

英secure as a city protected by a wall of metal and a moat of boiling water (idiom)​, well fortified, invulnerable to attack