Personally, I'd call the person wise. Really depends on the Reason Why the person is observing others. A person gaining wisdom would most likely observe wisely, meaning the person being observed wouldn't even know, but not to the Extreme. But a person just excessively watching someone, like staring, would be uncomfortable...Basically your question is unanswerable, unless you're more Specific.
A person who observes other people is commonly called an observer, an onlooker, or a spectator.
Because they are dating one person then go behind there back with another one that is why we call them cheaters.
A person who makes people happy can be referred to as a joy giver, happiness spreader, or simply a positive influence.
A person who laughs at others is typically referred to as a bully or a mocker. Their behavior can be hurtful and can negatively impact the well-being of those they are mocking.
People may call others stupid out of frustration, anger, or a desire to assert dominance. It can stem from a lack of empathy, insecurity, or a need to feel superior. Overall, name-calling like this is unproductive and harmful to relationships.
A person with a big ego can be called arrogant, conceited, or self-absorbed.
He observes what the other dogs are doing.
He observes what the other dogs are doing.
sommeone who hidding someting __ Vigilant or alert
An anthropologist studying a group of people who live in a similar manner to how people lived long ago would be known as a cultural anthropologist or an ethnographer. They would observe and document the customs, traditions, and way of life of the community to gain insights into their culture and practices.
hero
hypnotist
@ssh0le.
A zoologist
a plagiarist
A person who tortures and gets enjoyment out of it is called a sadist.
A namesake, if one person was named for the other.
A Medium