| responsible(adjective, smart, bright, competent, attentive) |
| responsive(adjective, understanding, open, keen, sharp) |
| scare(noun, verb, state, start, shock) |
| semaphore(noun, indication, alarm) |
| sensible(adjective, understanding, open, keen, smart) |
| sensitive(adjective, understanding, open, keen, sharp) |
| shock(noun, verb, start, alarm) |
| speedy(adjective, keen, energetic, active, fast) |
| stamp(noun, verb, indicate, indication) |
| startle(verb, alarm) |
| tip(noun, verb, order, information, sign) |
| warning signal(noun, expression, idiom, sign, guide) |
| zippy(adjective, moving, keen, sharp, bright) |
| advertent(intelligent, attentive, watchful, sharp-eyed) |
| advisory(noun, notice, warning) |
| all ears(expression, adjective, sharp, bright, lively) |
| canny(adjective, smart, bright, intelligent, cautious) |
| considerate(adjective, care, careful, thoughtful, cautious) |
| considering(adjective, intelligent, attentive, watchful, sharp-eyed) |
| deliberate(adjective, thoughtful, sober, cautious, prudent) |