wa·ter·tight/`wɔtə`taɪt; ˈwɔːtətaɪt/ adj 1 a watertight argument, agreement etc does not contain any mistakes or weaknesses which people can criticize 〔论点、协议等〕无懈可击的; 周密的: The police thought they had a watertight case. 警方认为此案证据确凿，无懈可击。 2 not allowing any water to get in or out 不透水的，密封的: a watertight container 密封的容器