Observant

This character observes and analyzes people they meet.

They usually do so to better understand them, judge their characters, or uncover their intentions, reactions or habits. Unlike pure curiosity, the intentions of such a person may be either good, bad, or neutral, are often backed by an ulterior motive, and are usually limited to certain people or environments.

Can also be applied to characters who observe and pay attention to their surroundings, sometimes even quickly noticing changes in people, environments, or even moods/atmospheres, but without reaching the knowledge or sharpness of being insightful.