In spanish, it is derived from latin (barbarus). At the beginning it was used to refer to all foreigners in general.
The romans (Roman Empire) would refer to all those that were not under the empire as "barbaros"
From there, it can be derived to mean other things such as:
he who commits violent, cruel acts.
uncivilized, rude
also can be used to enhance something else....as in an experience, a game, etc...