5
fussy(adjective, careful, thoughtful, sober, attentive)
5
judicious(adjective, understanding, cool, reasonable, sensible)
5
prompt(adjective, responsive, early)
5
scrupulous(adjective, complete, careful, sober, whole)
5
sharp-eyed(adjective, alert, intelligent, attentive, watchful)
5
thoughtful(adjective, reasonable, sensible, deliberate, restrained)
5
unsleeping(adjective, alert, careful, cautious, disturbed)
5
wide awake(expression, adjective, idiom, sharp, bright)
4
active(adjective, sharp, bright, lively, alert)
4
alive(adjective, cool, alert, significant, intelligent)
4
diligent(adjective, attentive)
4
eagle-eyed(adjective, alert, intelligent, attentive, watchful)
4
observing(adjective, understanding, keen, sensible, certain)
4
shrewd(adjective, sensible, careful, wise, tight)
4
thorough(adjective, complete, thoughtful, sober, whole)
4
wise(adjective, understanding, cool, reasonable, sharp)
3
absorbed(adjective, attentive)
3
all ears(expression, adjective, sharp, bright, lively)
3
brisk
3
cagey(adjective, sharp, bright, sensible, lively)
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APASmart Define. (2015). vigilant thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/vigilant/thesaurus/synonyms
ChicagoSmart Define. 2015. "vigilant thesaurus" https://smartdefine.org/vigilant/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, vigilant thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/vigilant/thesaurus/synonyms>.
MLASmart Define. "vigilant thesaurus" 10 April 2015. Web. 25 September 2026. <https://smartdefine.org/vigilant/thesaurus/synonyms>