| bright(adjective, smart, rational, intelligent, thoughtful) |
| brilliant(adjective, smart, bright, alert, perceptive) |
| broad-minded(adjective, moderate, rational, tolerant, flexible) |
| budget(adjective, modest, cheap, inexpensive, economy) |
| calm(adjective, quiet, sound, soft, moderate) |
| circumspect(adjective, sound, sensible, restrained, rational) |
| clean(adjective, good, appropriate, honest, sensible) |
| clear(adjective, sound, sensible, plain, rational) |
| clear-headed(adjective, calm, quiet, sensible, dark) |
| clever(adjective, smart, bright, sensible, alert) |
| cogent(adjective, sound, correct, sensible, solid) |
| coherent(adjective, sound, sensible, alert, rational) |
| comfortable(calm, easy, relaxed, suitable, substantial) |
| common(adjective, good, sensible, ordinary, usual) |
| commonsensible(adjective, sound, reason, sensible, sane) |
| competent(suitable, acceptable, adequate) |
| compos mentis(expression, adjective, idiom, sensible, rational) |
| composed(adjective, calm, quiet, sound, moderate) |
| conscious(adjective, sound, sensible, rational, sober) |
| consequent(adjective, good, sound, reason, sensible) |