airtight

1. ADJ If a container is airtight, its lid fits so tightly that no air can get in or out. 密封的

Store the cookies in an airtight container. 把饼干存放在一个密封的容器里。

2. ADJ An airtight alibi, case, argument, or agreement is one that has been so carefully put together that nobody will be able to find a fault in it. 无懈可击的[美国英语]