prizeless

From prize +‎ -less.

prizeless (not comparable)

1. Without a prize.
   • 2009, Jason Rosenhouse, The Monty Hall problem:

     Monty tells you that after you pick a door he will open a prizeless door from the remaining two, and that he will then give you the option of either staying with your original choice and getting a guaranteed bonus of $100 or switching to the one remaining unopened door without getting any bonus.