Synonyms for alert

condition of heightened watchfulness or preparation for action (noun)

a warning serves to make you more alert to danger (noun)

• alerting

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

• alarm
• alarum

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

• alarm

engaged in or accustomed to close observation (adj)

• watchful

quick and energetic (adj)

• brisk
• lively
• merry
• rattling
• snappy
• spanking
• zippy

mentally perceptive and responsive (adj)

• alive(p)
• awake(p)