Словарь синонимов английского языка - vigilant

(adj) watchful, alert, sharp, observant, guarded, circumspect, attentive, wakeful, cautious, careful, wary, chary, on one's guard, on the alert, on the lookout, eagle-eyed, hawk-eyed, Argus-eyed, on the qui vive, on one's toes, with one's eyes open, Colloq with one's eyes skinned or peeled: As long as we remain vigilant, they will never be able do take us by surprise.