形容詞 watertight:

1. not allowing water to pass in or out
2. without flaws or loopholes
   同義詞：unassailable, unshakable, bulletproof

1. As soon as the alarm went, the crew raced round shutting the watertight doors.
   警報一響，船員們跑來跑去把船上的密封門關(guān)緊。
2. Is this roof completely watertight?
   這屋頂一點也不漏嗎？
3. A watertight cylindrical vessel, open at the top and fitted with a handle; a bucket.
   桶一種不漏水的圓柱形容器，頂部敞開并安有把手; 水桶

wa.ter.tight

adj.（形容詞）
So tightly made that water cannot enter or escape.
水密的：制造之緊密以致水無法進入或漏出的
Having no flaws or loopholes; impossible to fault, refute, or evade:
無懈可擊的：沒有瑕疵或漏洞的；不可能錯誤、反駁或回避的：
例句：
a watertight alibi; a watertight contract.
無懈可擊的借口；嚴(yán)密的合同