2
understanding(adjective, keen, sensible, certain, alert)
2
undivided(adjective, whole)
2
waking(careful, restless, disturbed, conscious, sleepless)
2
well-prepared(careful, wise, tight, shrewd, prudent)
2
with it(expression, understanding, keen, sharp, bright)
1
apperceptive(adjective, understanding, keen, sensible, certain)
1
apprised(adjective, understanding, keen, sensible, certain)
1
armed
1
armed and ready(expression, idiom)
1
assured(adjective, understanding, keen, sensible, certain)
1
astute(adjective, understanding, cool, significant, intelligent)
1
au courant(expression, adjective, understanding, keen, sensible)
1
aux aguets
1
avid
1
be up on(adjective, careful, cautious, aware, attentive)
1
brainy(adjective, understanding, cool, significant, intelligent)
1
briefed
1
brilliant(adjective, cool, alert, significant, intelligent)
1
broad awake(expression, idiom, care)
1
calculating(restrained, careful, reserved, cautious, prudent)
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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>