A barbarian is quite literally a barbed Arian, someone who has facial hair and belongs to the Arian race. Typically these people were considered uncivilised since they weren't shaved and were unkempt altogether. Most were also part of warrior tribes like Norsemen and so forth. Over time, barbarianism was also associated with brutality, and now when we think the word barbarian we think of someone who's unruly to an extreme and most likely very violent and disrespectful, like barbaric table manners too. However, the word has nothing to do with these sorts of acts.
I myself am a barbed Arian, though I do not take to things typically associated with barbarianism, proving that facial hair does not affect ones activities. xd