Noun
1. condition of heightened watchfulness or preparation for action;
"bombers were put on alert during the crisis"2. a warning serves to make you more alert to danger
3. an automatic signal (usually a sound) warning of danger
Verb
1. warn or arouse to a sense of danger or call to a state of preparedness;
"The empty house alarmed him""We alerted the new neighbors to the high rate of burglaries"Adjective
1. very attentive or observant;
"an alert and responsive baby is a joy""caught by a couple of alert cops""alert enough to spot the opportunity when it came""constantly alert and vigilant, like a sentinel on duty"2. mentally responsive;
"an alert mind"3. not unconscious; especially having become conscious;
"the patient is now awake and alert"4. (usually followed by `to') showing acute awareness; mentally perceptive;
"alert to the problems""alive to what is going on""awake to the dangers of her situation""was now awake to the reality of his predicament"