I was actually leaning toward the common fantasy take on what is defining a person as a bastard. Even so - it is more on the note of being perturbed by someone's contrary actions than about anything else. I live in the Balkans too and in my country we don't really have a social concept for what a bastard is, because it would be too rude to call on someone about it. It could be used to call someone who's parents weren't married at the time of his/her birth( but if the father aknowedges the child or is taking care of it after it's born, people wouldn't use the word toward the child). The more common use would be about describing a child who doesn't know who his father is. But the word "fatherless" is more commonly used for that, since it's more descriptive of someone's situation without the inherit rudeness of the word bastard. I'd say the only way( at least in my country) you'd encounter the word bastard used to describe a child is if the mother( at the time of conceiving the child) is married or lives or is in relationship with Man A, but Man A has had nothing to do with the actual conceiving of said child, i.e. the mother was unfaithful and tried to hide the fact. Even so, it's directed more toward describing the immoral act done by the mother rather than for insulting the child that had nothing to do with how it was conceived. It could also apply to a situation where a father like Ned brings a child like John into his home, when it's obvious that John was conceived after Ned had begun his relationship with Catelyn, etc. We are mostly using the word to lovingly or not pointing to unconventional behavior, or cheekiness, or arrogance. And also as a slang substituting "bro", but this is usually found through the younger demographics, since it has somewhat childish/immature ring to it when it's used in that regard, because it's pronounced with different cadence( similar to the "wazaaaaa" thing from the commercial).