Definition: a person (especially a man) who leads an immoral life and is mainly interested in sexual pleasure

Libertine did not start out as a bad word. It came from an excellent family (Latin) and had a promising childhood (its first meaning was “freedman”). And then somewhere along the way the word fell in with a bad lot and its meaning took a turn for the worse. In the 16th century the word came to be associated with an antinomian religious sect based in France and the Netherlands, and perhaps due to this later took on the meaning that it typically carries today, which refers to a lack of morality. Libertine may be used to refer to a woman, but it is more commonly applied to men.