| low(adjective, close, quiet, soft, peaceful) |
| low-pitched(adjective, close, quiet, soft, low) |
| motionless(adjective, calm, quiet, smooth, tranquil) |
| muffled(adjective, close, quiet, soft, low) |
| mute(adjective, close, quiet, soft, low) |
| muted(adjective, close, quiet, soft, low) |
| noiseless(adjective, close, quiet, smooth, soft) |
| not saying boo(expression, adjective, idiom, close, quiet) |
| pacific(adjective, calm, quiet, smooth, tranquil) |
| placid(adjective, calm, quiet, smooth, tranquil) |
| quiescent(adjective, close, quiet, soft, low) |
| quiet(adjective, calm, close, smooth, soft) |
| quieted(adjective, close, quiet, soft, low) |
| reserved(adjective, close, quiet, soft, low) |
| restful(adjective, calm, quiet, smooth, tranquil) |
| reticent(adjective, close, quiet, soft, low) |
| sealed(adjective, calm, quiet, smooth, tranquil) |
| secretive(adjective, close, quiet, soft, low) |
| serene(adjective, calm, quiet, smooth, gentle) |
| silent(adjective, calm, close, quiet, smooth) |