A drifter is a title given to a person who moves from place-to-place rather than settling down.
After Quark accidentally killed Kozak in 2371, Odo told him that the Klingon "wasn't just some drifter passing through" Deep Space 9, but the leader of the House of Kozak. (DS9: "The House of Quark")
In 2372, when Tom Paris pretended to be leaving USS Voyager to help to locate a mole in the crew, he said to Neelix that he considered himself to be a drifter. (VOY: "Investigations")