1. vigilant Alert, ready, and wide-awake refer to a watchful promptness for action. Ready suggests thoughtful preparation; the wandering Indian is alert, the trained soldier is ready. Ready express Synonyms: alert, active, lively, prepared, vigilant, brisk, nimble, prompt, watchful, hustling, on the watch, ready, wide-awake Antonyms: drowsy, dull, heavy, inactive, slow, sluggish, stupid
Synonyms for vigilant 
