A dirty, grimy, sleazy, or disreputable person.
A poor climber, alpinist, skier or other outdoorsman who lives cheaply, without normal employment, and with few amenities in order to spend as much time on their sport as possible. Used praisingly.
A poor migratory farm worker in Ireland, often viewed as a rascal or mischievous and cunning person.
A good-for-nothing person.