形容词

1. 不透水的;水密的
Something that is watertight does not allow water to pass through it, for example because it is tightly sealed.

2. (事实、论点或协议)严密的，无懈可击的
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.

1. without flaws or loopholes

e.g. an ironclad contract
a watertight alibi
a bulletproof argument

Synonym: unassailableunshakablebulletproof

2. not allowing water to pass in or out