adj.不漏水的；無(wú)懈可擊的
We had a couple of suspicious characters but their alibis are watertight. 我們中有幾位多疑的人，但是他們的陰謀無(wú)懈可擊。
The system, of course, is not watertight. 當(dāng)然這套系統(tǒng)也不是天衣無(wú)縫的。
