nothing ever leaks out;careful and thorough ❍ 同你共事，你是“马蹄刀瓢里切菜一滴水也不漏”，总不肯放出钱来。(《儒林外史》234)I’ve never worked with anyone so close-fisted. You can’t bear parting with a cent!/他作了一个周密的计划，真是～。He has made a well-conceived plan. It is really careful and thorough.
滴水不漏dī shuǐ bù lòu
一点水也漏不出来。比喻严守秘密或不露破绽。leakproof, careful and thorough, nothing ever leaks out, watertight