This is the 1128th most frequent Swedish word.
charles
"Charles" is not a Swedish word; it is a proper noun, commonly a given name.
In this sentence, 'Charles' is used as a proper noun referring to a person.
Charles är en mycket artig kille.
Charles is a very polite guy.
Here 'Charles' is again a proper noun, referring to a specific individual whom the speakers know and plan to visit.
Vi ska besöka Charles nästa vecka.
We are going to visit Charles next week.
In this instance, 'Charles' is used to address or indicate a certain person named Charles, who is being indirectly discussed in the conversation.