Define 4th Person Meaning

Also sometimes called the 0th person (e.g. in the Finnish language)
It is grammatical tone used for generative indefinite referents.
People speak in 4th person when they want to make a general statement that applies to not just one particular person, or scenario, but instead universally. This is usually in the context of administering a command, asserting a universal moral claim, or in an academic lecturing style.
It is not typically used in everyday conversation. If you speak in the 4th person to someone, it can come across as if you are being impersonal/depersonalizing them, or ordering them / lecturing them.

Some linguists believe that the 4th person is not a real thing, but instead is actually just an extension of the 3rd person. If you take the perspective that the subject in 4th person perspective is an actual existing entity (e.g. a human, animal etc.), then it is the 3rd person, but if you do not assign a actual existing entity, then it remains in the general indefinite. In this regard, it is similar to the mathematical / logical statements, which exist without a subject.

Sometimes it used in a subtle ways such as when people make moral claims and use the term 'you' as a subject, but it is used as an indefinite general 'you' as opposed to a specific person that is being spoken to. Usually people do this unknowingly, and it is usually so subtle that it doesn't call for any acknowledgement in conversation.

When someone talks about you , to you

Basically speaking in 3rd person, but talking about another person who is with you.

... still working on this definition.

1. When you have split personalities (skitzo) and one of the personalities talks about the other personality(ies) as if they are another body(ies).

2. Talking about your alter ego as if they are another person.

When an author is narrating about a person a person who is skitzo talking about their other personality consciously.