| impassable(adjective, solid, dense, unaffected, unyielding) |
| latent(obscure, dark, secret, unknown, hidden) |
| magic(obscure, deep, mysterious) |
| mysterious(obscure, solid, dark, deep, unknown) |
| resistant(unaffected, unyielding, unbending, impervious, unreceptive) |
| secluse(close, quiet, private, isolated, secluded) |
| seclusive(close, quiet, private, isolated, secluded) |
| secret(close, quiet, obscure, complex, deep) |
| secured(adjective, closed) |
| sequestered(close, quiet, obscure, dark, unknown) |
| undisclosed(obscure, dark, secret, unknown, hidden) |
| unrevealed(obscure, dark, deep, mysterious, unknown) |
| bulletproof |
| reclusive(adjective, close, quiet, private, isolated) |
| Delphic |
| air-locked(adjective, tight, proof, impervious) |
| air-proof(adjective, tight, proof, impervious) |
| classified |
| closet(close, quiet, private, isolated, secluded) |
| clouded(obscure, dark, secret, unknown, hidden) |