from The Century Dictionary.
- noun The driver of a drag or coach.
- noun A thief who follows carriages to cut away luggage from behind.
- noun One engaged in dragging a a river, lake, pond, harbor, or the like, in search of something.
Sorry, no etymologies found.
"riatta" over their heads, he had them as much under his command as ever a crack dragsman had his four-in-hand in the good old coaching times of my own dear England.