| under cover(expression, adjective, obscure, dark, isolated) |
| undetected(obscure, dark, secret, unknown, hidden) |
| undisclosed(obscure, dark, secret, unknown, hidden) |
| unexposed(obscure, dark, secret, unknown, hidden) |
| unknown(obscure, dark, secret, hidden, concealed) |
| unrevealed(adjective, obscure, dark, unknown, hidden) |
| unseen(obscure, dark, secret, unknown, hidden) |
| water-proof(adjective, tight, proof, impervious, hermetic) |
| water-tight(adjective, tight, proof, impervious, hermetic) |
| waterproof(adjective, tight, proof, impervious, hermetic) |
| withheld(obscure, dark, secret, unknown, hidden) |
| apprenticed(unknowing, unbriefed) |
| backstage(unknowing, unbriefed) |
| backstairs(unknowing, unbriefed) |
| behind the curtain(expression, idiom, unknowing, unbriefed) |
| behind the scenes(expression, idiom, unknowing, unbriefed) |
| beyond range(expression, isolated, reclusive, uncompanionable) |
| birdbrained(unknowing, unbriefed) |
| blind to(expression, unknowing, unbriefed) |
| blockaded(isolated, reclusive, uncompanionable) |