One who is Irish and tends to wear multiple irish rings at one time. He/she is coined a thief because the rings are placed on random fingers such as thumbs, pinkies, forefingers, and are being worn at the same time (as if this person has just stolen all of these rings).
"Paddy..... you got a lot of rings on today! What's up with that? Do those all even belong to you? You are a regular ole Irish thief!"