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. 把餅乾存放在一個密封的容器裡。

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. 無懈可擊的[美國英語]