| responsible(smart, bright, brainy) |
| right-minded(adjective, sensible, rational, healthy, stable) |
| righteous(adjective, good, sound, right, pure) |
| safe(adjective, good, sound, fair, proper) |
| sagacious(adjective, sound, reasonable, sensible, rational) |
| sage(adjective, sound, reasonable, smart, bright) |
| salubrious(adjective, good, pure, healthy, decent) |
| sapient(sensible, rational, healthy, stable, sober) |
| savvy(bright, sharp-witted, quick-thinking) |
| secure(solid, proper, stable, normal, accepted) |
| self-possessed(calm, sound, reasonable, sensible, rational) |
| sentient(adjective, reasonable, rational, intelligent, sober) |
| sharp(smart, bright, enlightened, brainy, sharp-witted) |
| sharp as a tack(expression, idiom, smart, bright, skillful) |
| shrewd(adjective, reasonable, keen, sharp, smart) |
| smart(bright, skillful, brainy, sharp-witted, nimble-witted) |
| smart as a whip(expression, idiom, smart, bright, active) |
| stable(sound, reasonable, sensible, solid, proper) |
| standing up(expression, adjective, good, sound, sharp) |
| steady(calm, sound, reasonable, sensible, rational) |