| concentrated |
| conservative(thoughtful, sober, cautious, prudent, wary) |
| contemplating(alert, intelligent, attentive, watchful, sharp-eyed) |
| controlled(cautious, tactful, circumspect) |
| conversant(careful, knowledgeable, aware, attentive, wary) |
| cool(adjective, deliberate, alert, familiar, thoughtful) |
| correct(alert, intelligent, attentive, watchful, scrupulous) |
| curious |
| deducing(alert, intelligent, attentive, watchful, sharp-eyed) |
| designing |
| detecting(alert, intelligent, attentive, watchful, sharp-eyed) |
| discovering(alert, intelligent, attentive, watchful, sharp-eyed) |
| discriminating(adjective, alert, careful, intelligent, cautious) |
| eager(kind, alert, loving, intelligent, considerate) |
| eagle-eyed(alert, intelligent, attentive, watchful, sharp-eyed) |
| enlightened(adjective, alert, familiar, wise, knowledgeable) |
| excogitative |
| eye |
| familiar(adjective, alert, wise, knowledgeable, responsive) |
| fast on the draw(expression, idiom, sharp, bright, lively) |