adj.
1.very attentive or observant
2.mentally responsive
3.not unconscious
4.(usually followed by `to') showing acute awareness alert n.
1.condition of heightened watchfulness or preparation for action
2.a warning serves to make you more alert to danger
3.an automatic signal (usually a sound) warning of danger alert v.
1.warn or arouse to a sense of danger or call to a state of preparedness