| hermetic(adjective, tight, proof, impervious) |
| airtight(adjective, tight, proof, impervious, hermetic) |
| sealed(adjective, tight, proof, impervious, hermetic) |
| tight(adjective, proof, impervious, hermetic) |
| watertight(adjective, tight, proof, impervious, hermetic) |
| airproof(adjective, tight, proof, impervious, hermetic) |
| pressure-tight(adjective, tight, proof, impervious, hermetic) |
| air-tight(adjective, tight, proof, impervious, hermetic) |
| hidden(verb, adjective, secret, unknown, isolated) |
| QT(adjective, secret, unknown, isolated, hidden) |
| abstruse(obscure, dark, secret, unknown, hidden) |
| air-locked(adjective, tight, proof, impervious, hermetic) |
| air-proof(adjective, tight, proof, impervious, hermetic) |
| chemic |
| chemical |
| close(obscure, dark, secret, unknown, hidden) |
| clouded(obscure, dark, secret, unknown, hidden) |
| cryptic(obscure, dark, secret, unknown, hidden) |
| dampproof(adjective, tight, proof, impervious, hermetic) |
| eclipsed(obscure, dark, secret, unknown, hidden) |