69 entries under vigilant topic. ×

8
guarded(adjective, adverb, reasonable, keen, sensible)
8
on the ball(expression, adjective, idiom, keen, sharp)
8
sharp-eyed(adjective, sympathetic, alert, witting, attentive)
7
intelligent(adjective, understanding, cool, sharp, smart)
7
interested(adjective, strong, open, friendly, intense)
7
meticulous(adjective, alert, careful, sober, attentive)
7
penetrating(adjective, understanding, strong, sharp, smart)
7
scrupulous(adjective, alert, careful, thoughtful, sober)
6
diligent(adjective, attentive)
6
sensitive(adjective, understanding, open, kind, keen)
6
wakeful(adjective, keen, alert, careful, restless)
5
alive(adjective, cool, sensible, alert, significant)
5
bright(adjective, open, cool, sharp, friendly)
5
concerned(adjective, kind, friendly, deliberate, alert)
5
conscientious(adjective, careful, thoughtful, sober, considerate)
5
discreet(adjective, understanding, kind, keen, sharp)
5
solicitous(adjective, kind, deliberate, alert, careful)
4
chary(adjective, reasonable, sensible, deliberate, restrained)
4
deliberate(adjective, cool, kind, friendly, alert)
4
judicious(adjective, understanding, cool, reasonable, keen)
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APASmart Define. (2016). observant thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/observant/thesaurus/synonyms
ChicagoSmart Define. 2016. "observant thesaurus" https://smartdefine.org/observant/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2016, observant thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/observant/thesaurus/synonyms>.
MLASmart Define. "observant thesaurus" 29 March 2016. Web. 29 September 2026. <https://smartdefine.org/observant/thesaurus/synonyms>