What is a…
libertine

This word is found only Acts 6:9. It is one who once had been a slave, but who has been set free, or the child of such a person.

In this case the name probably denotes those descendants of Jews who had been carried captives to Rome as prisoners of war by Pompey and other Roman generals in the Syrian wars, and had afterwards been liberated. In 19 AD these manumitted Jews were banished from Rome. Many of them found their way to Jerusalem, and there established a synagogue.