| soft(adjective, close, quiet, low, peaceful) |
| soft-spoken(adjective, quiet, gentle, aloof, peaceful) |
| soundless(adjective, close, quiet, smooth, soft) |
| sparing(aloof, reserved, reticent, uncommunicative) |
| speechless(adjective, close, quiet, soft, low) |
| stable(adjective, calm, quiet, smooth, tranquil) |
| stagnant(adjective, calm, quiet, smooth, tranquil) |
| standoffish(adjective, quiet, gentle, aloof, reserved) |
| static(adjective, calm, quiet, smooth, tranquil) |
| stationary(adjective, calm, quiet, smooth, tranquil) |
| still(adjective, calm, close, quiet, soft) |
| stilled(adjective, close, quiet, soft, low) |
| stock-still(adjective, calm, quiet, smooth, tranquil) |
| surreptitious |
| tranquil(adjective, calm, quiet, smooth, gentle) |
| undercover(mysterious, private, reticent, taciturn, uncommunicative) |
| undisturbed(adjective, calm, quiet, smooth, tranquil) |
| unemotional |
| unexpressed(adjective, close, quiet, soft, low) |
| unexpressive(aloof, reserved, reticent, uncommunicative) |