In the literal sense, a person cannot just disappear from human sight without any explanation or process. Humans are visible beings, and if they are present in a particular location, they can be observed by others in that vicinity, assuming no extraordinary circumstances are involved.
However, there are situations where it may seem like a person has disappeared, but there’s usually a logical explanation for it:
Hiding or Camouflage:
A person can hide themselves intentionally or unintentionally, making it difficult for others to see them. Camouflage techniques, blending into the surroundings, or taking cover behind objects can make someone harder to spot.
Certain environmental conditions or optical illusions might make it seem like a person has vanished or blended into their surroundings. This can happen in particular lighting conditions or environments with complex patterns.
At a considerable distance, a person may appear too small to be seen with the naked eye, giving the impression of disappearing.
A person might disappear from sight behind buildings, trees, or other obstacles.
As of my last update in September 2021, no technology exists that can make a person truly invisible to the naked eye. However, research in advanced optics and metamaterials continues, so this could change in the future.
Magic and Fiction:
In the realm of fiction, movies, and literature, there are stories where characters possess abilities to become invisible or vanish magically. However, these are fictional concepts.
In summary, while a person cannot truly vanish from human sight without logical explanations, there are various circumstances and conditions that can create the illusion of someone disappearing.