| alert(adjective, adverb, keen, sharp, lively) |
| vigilant(adjective, adverb, lively, careful, aware) |
| watchful(adjective, adverb, sharp, lively, alert) |
| observant(adjective, adverb, sharp, lively, alert) |
| wary(adjective, adverb, sharp, lively, alert) |
| on guard(expression, adjective, adverb, sharp, lively) |
| attentive(adjective, keen, sharp, lively, restrained) |
| cautious(adjective, adverb, keen, restrained, alert) |
| circumspect(adjective, keen, sharp, lively, restrained) |
| heedful(adjective, adverb, sharp, lively, alert) |
| mindful(adjective, adverb, alert, careful, considerate) |
| all ears(expression, adjective, sharp, lively, careful) |
| aware(adjective, keen, alert, careful, considerate) |
| eagle-eyed |
| guarded(adjective, adverb, keen, alert, careful) |
| on the ball(expression, adjective, sharp, lively, alert) |
| on the watch(expression, adjective, idiom, adverb, alert) |
| open-eyed(adjective, keen, sharp, bright, alert) |
| sharp(adjective, keen, bright, lively, alert) |
| wakeful(adjective, keen, sharp, alert, careful) |