| sly(adjective, quiet, intriguing) |
| sneak(adjective, restricted, discreet) |
| sneaky(adjective, quiet, intriguing) |
| spectacular(adjective, behavior, theatrical) |
| stagy(adjective, behavior, melodramatic, theatrical, overemotional) |
| stealthy(adjective, quiet, intriguing) |
| strange(adjective, obscure, unknown, unrevealed) |
| surreptitious(adjective, quiet, intriguing) |
| suspense(noun, anticipation) |
| theatrical(adjective, behavior, overemotional, blood-and-thunder) |
| under-the-counter(adjective, hidden, fraudulent) |
| under wraps(expression, adjective, hidden, fraudulent) |
| undercover(adjective, quiet, intriguing) |
| underground(adjective, hidden, fraudulent) |
| underhand(adjective, hidden, fraudulent) |
| undisclosed(adjective, obscure, unknown, unrevealed) |
| unenlightened(adjective, obscure, unknown, unrevealed) |
| unfrequented(adjective, obscure, unknown, unrevealed) |
| unintelligible(adjective, obscure, unknown, unrevealed) |
| unknown(adjective, obscure, unrevealed) |