When something or a space is described as having no openings, it could mean that it is completely closed, sealed, or shut. Synonyms for having no openings include airtight, sealed, tightly shut, closed, impenetrable, impervious, hermetic, and watertight. Airtight refers to something that is completely sealed, so that no air can pass through it. Sealed and tightly shut both imply that access is denied because something is completely closed, often with a cover or lid. Impenetrable and impervious suggest that a barrier is in place, preventing anything from entering or escaping. Hermetic and watertight mean that it is completely tight and secure, preventing anything from escaping or entering, often used to describe sealed containers for storage purposes.