Entry Word: alert

Function: adjective

Meaning: 1 paying close attention usually for the purpose of anticipating approaching danger or opportunity <Susan needed to stay alert throughout the train ride so as not to miss her stop>

Synonyms attentive, awake, open-eyed, vigilant, watchful, wide-awake

Related Words alive, aware, conscious, sensitive; heedful, mindful, observant, observing, sharp, sharp-eyed; sleepless, wakeful; careful, cautious, chary, wary; prepared, ready

Phrases on guard, on the alert

Near Antonyms absent, absentminded, absorbed, abstracted, daydreaming, dazed, distracted, dreaming, dreamy, engrossed, faraway, insensible, oblivious, preoccupied; asleep, sleeping, unaware, unconscious, unknowing, unperceiving, unseeing, unwitting; careless, heedless, inattentive, unheeding, unmindful, unobservant, unobserving, unthinking, unwary; unprepared, unready

2 having or showing a close attentiveness to avoiding danger or trouble <warned us to be alert to the presence of pickpockets on the crowded bus> — see careful 1
3 having or showing quickness of mind <an alert and well-trained sheep dog who can handle difficult situations> — see intelligent 1
4 having or showing the ability to respond without delay or hesitation <an alert force of commandos, ready to go on a mission at a momentʼs notice> — see quick 1