nothing ever leaks out;careful and thorough ? 同你共事，你是“馬蹄刀瓢里切菜一滴水也不漏”，總不肯放出錢來。(《儒林外史》234)I’ve never worked with anyone so close-fisted. You can’t bear parting with a cent!/他作了一個周密的計劃，真是～。He has made a well-conceived plan. It is really careful and thorough.
滴水不漏dī shuǐ bù lòu
一點水也漏不出來。比喻嚴守秘密或不露破綻。leakproof, careful and thorough, nothing ever leaks out, watertight