History
History
Synonyms
UK
US
Meaning:
alert

fully awake and ready to act, speak etc

attentive, lively

awake

not sleeping; having woken

conscious; alert

prepared

that has been made ready in advance

ready in body or mind

vigilant

keeping careful watch

careful, watchful

wary

careful about possible danger or trouble

careful, cautious

ON GUARD as in Wiktionary
ON GUARD as in Wikipedia