adjective. Vigilantly attentive; watchful: synonym: careful.

adjective. Mentally responsive and perceptive; quick.

adjective. Brisk or lively in action.

noun. A signal that warns of attack or danger.

noun. A condition or period of heightened watchfulness or preparation for action.

transitive verb. To notify of approaching danger or action; warn.

idiom. (on the alert) Watchful and prepared for danger, emergency, or opportunity.

Active in vigilance; watchful; vigilantly attentive.

Moving with celerity; brisk; active; nimble: as, “an alert young fellow,” Addison, Spectator, No. 403.

Lively, agile, quick, prompt, ready, spry.

noun. An attitude of vigilance; watch; guard: especially in the phrase on or upon the alert, upon the watch; on the lookout; guarding against surprise or danger: as, “the readiness of one on the alert,” Dickens.

adjective. Watchful; vigilant; active in vigilance.

adjective. Brisk; nimble; moving with celerity.

noun. An alarm from a real or threatened attack; a sudden attack; also, a bugle sound to give warning.

noun. on the lookout or watch against attack or danger; ready to act.

adjective. Attentive; awake; on-guard.

noun. An alarm.

noun. A notification of higher importance than an advisory.

verb. To give warning to.

adjective. engaged in or accustomed to close observation

adjective. mentally perceptive and responsive

verb. warn or arouse to a sense of danger or call to a state of preparedness

adjective. quick and energetic

noun. a warning serves to make you more alert to danger

noun. condition of heightened watchfulness or preparation for action

noun. an automatic signal (usually a sound) warning of danger

"However, in this alert is an unusual warning about the state of Durango:"

nimble  

Argus-eyed  aware  cognisant  cognizant  energetic  

Bert  Curt  Evert  Insert  Kurt  

able  attentive  confident  eager  intelligent  

Klaxon  Mayday  SOS  active  active  

alerted  alerting  alertness  alerts