周密 | zhōu mì | careful / thorough / meticulous / dense / impenetrable | |
密不透风 | mì bù tòu fēng | sealed off / impenetrable | |
水泄不通 | shuǐ xiè bù tōng | lit. not one drop can trickle through (idiom) / fig. impenetrable (crowd, traffic) | |
铜墙铁壁 | tóng qiáng tiě bì | copper wall, iron bastion (idiom) / impenetrable defense | |
高城深池 | gāo chéng shēn chí | high walls and deep moat (idiom) / impenetrable defense | |
弥蒙 | mí méng | impenetrable thick fog or smoke |