Zhè wèi lǜshī biànhù dīshuǐbùlòu, zuìzhōng yíngdé le guānsi.
The lawyer's defense was airtight and ultimately won the case.
Tips
history
Traced to the Song-era 《朱子语类·易三》: 又要说得极密处无缝罅，盛水不漏 — 'one must speak so tightly that there is no crack, holding water without leaking.' Originally about rigorous argument; now applied broadly to airtight work.
usage
Praise for arguments, alibis, security, plans, and accounts that leave no gap. Can also describe someone holding money so tightly they never let a cent slip away — context determines which sense.
