Vigilant
vig·i·lant
ˈvijələnt/
adjective
keeping careful watch for possible danger or difficulties.
"the burglar was spotted by vigilant neighbors"
synonyms: watchful, observant, attentive, alert, eagle-eyed, hawk-eyed, on the lookout, on one's toes, on the qui vive; More
antonyms: inattentive...