water tight

基本解释

Reattach cover plate to make an air and water tight seal.
重新固定盖板，并紧密密封防止空气和水通过。
Flexibility and hosing test for small water tight hatch cover(water tight door and window).
水密小舱口盖（水密门、窗）启闭灵活性、冲水检查。
Flexibility and hosing test for small water tight hatch cover( water tight door and window).
水密小舱口盖（密门、）闭灵活性、水检查。

And at some point, these pits weren't perfectly water-tight, some water would have got into one of them, and you might have got fermentation that way.
NPR: Looking at the World Through Beer Glasses
To impress lending officers, new (and established) entrepreneurs need water-tight business plans with defined, clearly articulated and reasonable financial projections.
FORBES: When Bad Credit Haunts A Good Idea
Consent forms for film and TV tend to follow a water-tight structure that is standard across the industry.
FORBES: Magazine Article

Something that is watertight does not allow water to pass through it, for example, because it is tightly sealed.
A watertight case, argument, or agreement is one that has been so carefully put together that nobody will be able to find a fault in it.