Rarely do words generate independently. More often words beget words, which then beget other words. And as with people, it can sometimes be surprising that two members of the same family are actually related. Take the words glance and glacier, for example. There is a slight family resemblance (gla-), but the two words have such different meanings that it can be hard to believe they have anything in common. But they do.
Think slippery. Both words stem from the Old French word glace, meaning ice. A glacier is a giant mass of accumulated ice. The English word glance first referred to what we now call a glancing blow, or something that barely touches before it slips on past. In time a glance came to mean what it does today, a brief look. A man, for example, may avoid looking directly at an attractive woman but, instead, will glance at her somewhat furtively in order to slip past the attention of the woman and, perhaps, his own wife.
Another example: The Romans called a beard a barbus, from which came the English word barber. An arrow was once called a barb because of those feathers at the end, which reminded somebody of a beard. Other sharp objects became known as barbs, leading to barbed wire. Barbados got its name from Spanish explorers because the islands had many native figs that appeared to be bearded. The tribesmen who overran a region in northern Italy had long beards, or longa barba. The region became known as Lombardy as result.
No, the name Barbara is not a descendant of the Latin barbus. It comes, instead, from another word meaning strange or foreign, the same source from which barbarian comes. I'm not sure this will be much comfort to all the Barbaras out there.