| chirpy(adjective, feature, state, trait) |
| civil(adjective, quiet, cool, moderate, gentle) |
| clammed up(expression, adjective, calm, quiet, smooth) |
| cloistered |
| close-mouthed(adjective, calm, quiet, smooth, tranquil) |
| closed(adjective, calm, quiet, smooth, tranquil) |
| comfy(adjective, calm, quiet, light, smooth) |
| commodious(adjective, calm, quiet, light, smooth) |
| compassionate |
| complacent(adjective, calm, cool, steady, tranquil) |
| constant(calm, quiet, sound, friendly, whole) |
| content(adjective, calm, quiet, light, smooth) |
| continuous(verb, adjective, quiet, sound, soft) |
| convivial(adjective, feature, state, trait) |
| cool as cucumber(expression, adjective, idiom, calm, quiet) |
| cosy |
| cozy(adjective, calm, quiet, light, smooth) |
| creamy(adjective, quiet, soft, gentle, flat) |
| cursive(adjective, calm, quiet, light, smooth) |
| cushy(adjective, calm, quiet, light, smooth) |