11
awake(adjective, understanding, cool, reasonable, keen)
10
chary(adjective, reasonable, sensible, deliberate, restrained)
10
on the ball(expression, adjective, idiom, sharp, bright)
10
wide-awake(adjective, sharp, bright, lively, alert)
8
jealous(adjective, wary)
8
keen(adjective, understanding, sensible, certain, alert)
8
provident(adjective, sensible, careful, thoughtful, sober)
7
on the alert(expression, adjective, idiom, care, alert)
7
protective(adjective, careful, thoughtful, sober, attentive)
7
ready(adjective, sharp, bright, excited, lively)
7
sleepless(adjective, alert, careful, restless, disturbed)
6
conscientious(adjective, deliberate, alert, careful, caring)
6
conscious(adjective, understanding, cool, keen, sensible)
6
discreet(adjective, sensible, restrained, careful, thoughtful)
6
intent(adjective, feature, characteristic, complete, detail)
6
nimble(adjective, smart, dexterous)
6
prepared(adjective, excited, ready, anxious, alert)
5
acute(adjective, alert, careful, perceptive, attentive)
5
agog(adjective, alert, careful, attentive, watchful)
5
argus-eyed
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APASmart Define. (2015). vigilant thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/vigilant/thesaurus/synonyms
ChicagoSmart Define. 2015. "vigilant thesaurus" https://smartdefine.org/vigilant/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, vigilant thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/vigilant/thesaurus/synonyms>.
MLASmart Define. "vigilant thesaurus" 10 April 2015. Web. 24 September 2026. <https://smartdefine.org/vigilant/thesaurus/synonyms>