The core of both of those words is "commune", to be in harmony with others. Communism hardly lives up to its name, but community often does.
As I have stated before, the defining commonality of many libertarians is their disdain and contempt for any society (yes socialism uses the same base word). There is a simple line from a famous piece of writing that I think can determine the difference between a "conservative" and a "libertarian":
Then the LORD said to Cain, "Where is your brother Abel?"
"I don't know," he replied. "Am I my brother's keeper?"
Most libertarians would answer "no".
That nails it. I've been shocked a few times by the total selfishness and hatred of government that gets espoused in the name of "liberty".
Without someone to defined and enforce the rules, nobody gets to play the game, including libertarians.
Voluntarily helping another, ie charity, is entirely compatible with libertarianism. If you ask us "Are you your brother's keeper?" We say, "Yes, when we want to be."
If we are denied that choice, the question is not "Are you your brother's keeper?". It becomes "Are you your brother's slave?"
"I don't know," he replied. "Am I my brother's keeper?""
Cain killed his brother Abel. The passage gives no more than Cain's attempt to weasel out of acknowledging he killed Abel. You use it as if God gives a command for the elightened of the world to run the lives of their fellows. He didn't! He gave all men a Free will and commanded them all to respect that gift as He does. What part of though shalt not steal don't you get?