| muted(adjective, close, quiet, soft, low) |
| noiseless(adjective, close, quiet, smooth, soft) |
| noncommittal(adjective, quiet, gentle, aloof, peaceful) |
| not saying boo(expression, adjective, idiom, close, quiet) |
| offish(quiet, gentle, aloof, reserved, reticent) |
| on the QT(expression, idiom, reserved, reticent, taciturn) |
| pacific(adjective, calm, quiet, smooth, tranquil) |
| placid(adjective, calm, close, quiet, smooth) |
| prim(adjective, quiet, gentle, aloof, peaceful) |
| quiescent(adjective, close, quiet, soft, low) |
| quieted(adjective, close, quiet, soft, low) |
| restful(adjective, calm, quiet, smooth, tranquil) |
| sealed(adjective, calm, quiet, smooth, tranquil) |
| secret |
| sedate(adjective, quiet, gentle, aloof, peaceful) |
| self-controlled(adjective, reserved) |
| self-restrained(adjective, reserved) |
| sententious(aloof, reserved, reticent, uncommunicative) |
| serene(adjective, calm, close, quiet, smooth) |
| smooth(adjective, calm, quiet, tranquil, silent) |