A Strag is someone who is NOT a hitchhiker and generally used to refer to someone on board a ship. If a person with a towel approaches a strag, the strag will assume that the towel-carrying person will also be "in possession of a toothbrush, face flannel, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet weather gear, space suit etc., etc" The strag will be happy to lend any of these objects to the hitchhiker.