| cool-headed(adjective, calm, quiet, cool, moderate) |
| cool as cucumber(expression, adjective, idiom, calm, quiet) |
| credible(adjective, open, sound, honest, sensible) |
| deductive(sound, reasonable, sensible, reasoning, intellectual) |
| deep(adjective, good, reasonable, keen, sensible) |
| deliberate(adjective, calm, quiet, sound, reasonable) |
| deliberative(adjective, reasonable, keen, deep, rational) |
| detached(adjective, calm, quiet, cool, moderate) |
| discerning(adjective, sound, reasonable, sensible, rational) |
| disciplined(adjective, calm, quiet, reasonable, sensible) |
| disimpassioned(adjective, calm, relaxed, tranquil, easygoing) |
| down-to-earth(adjective, calm, hard, sound, reasonable) |
| drab(adjective, calm, quiet, reasonable, sensible) |
| earnest(adjective, calm, quiet, reasonable, keen) |
| earthy(hard, sound, reasonable, sensible, practical) |
| easy(adjective, calm, quiet, relaxed, tranquil) |
| easygoing(adjective, calm, quiet, cool, relaxed) |
| engrossed(adjective, reasonable, keen, deep, rational) |
| equanimous |
| equilibrious |