observant

Definitions

Quick to notice or perceive things; alert.

Diligent in observing a law, rule, or custom.

Examples

She is a very observant person who notices even the smallest changes in her environment.

The observant detective quickly spotted the subtle clue that everyone else had missed.

Synonyms

attentive alert vigilant perceptive watchful sharp keen

Antonyms

inattentive oblivious unobservant distracted heedless negligent unaware