This is the 14579th most frequent German word.
luftdicht
Airtight.
The word 'luftdicht' describes the state of the closure, implying it does not allow air to enter or exit.
Die Dose wurde luftdicht verschlossen, damit die Kekse frisch bleiben.
The can was sealed airtight to keep the cookies fresh.
Here, 'luftdicht' functions as an attributive adjective modifying 'Behälter,' indicating their property of being impenetrable by air.
Um die Zutaten gut aufzubewahren, benötigt man luftdichte Behälter.
To store the ingredients well, one needs airtight containers.
In this sentence, 'luftdicht' is used as part of the explanation for maintaining the goods' quality, relating to packaging.