- observant - paying close attention especially to details
Antonym: inattentive (indirect, via attentive)
- observant, observing - quick to notice; showing quick and keen perception
Antonyms: unperceptive, unperceiving (indirect, via perceptive)
- law-abiding, observant - (of individuals) adhering strictly to laws and rules and customs; "law-abiding citizens"; "observant of the speed limit"
Antonym: unlawful (indirect, via lawful)