What is "fremen"

The Fremen are a group of people in the fictional Dune universe created by Frank Herbert. First appearing in the 1965 novel Dune, the Fremen inhabit the desert planet Arrakis (also known as Dune), which is the sole known source of the all-important spice melange in the universe. Long overlooked by the rest of the Imperium and considered backward savages, in reality they are an extremely hardy people and exist in large numbers. The Fremen had come to the planet thousands of years before the events of the novel as the Zensunni Wanderers, a religious sect in retreat. As humans in extremis, over time they adapt their culture and way of life to survive and thrive in the incredibly harsh conditions of Arrakis. The Fremen are distinguished by their fierce fighting abilities and adeptness at survival in these conditions. With water such a rare commodity on the planet, their culture revolves around its preservation and conservation. Herbert based their culture, in part, on the desert-dwelling Bedouin and Tuaregs.