Airtight and Watertight

Airtight adjective - Not allowing air or gas to pass in or out.

Watertight is a synonym for airtight in closed topic. In some cases you can use "Watertight" instead an adjective "Airtight", when it comes to topics like foolproof. popular alternative

Watertight adjective - Not allowing water to pass in or out.

Airtight is a synonym for watertight in impenetrable topic. You can use "Airtight" instead an adjective "Watertight", if it concerns topics such as sealed, foolproof, impervious to water. popular alternative