Limited Recourse Debt
  
See: Non-Recourse Debt.
You borrowed $10,000. You promised to pay it back. But...you didn't. Really shouldn't have played the ponies.
Luckily for you, the $10k you borrowed was from a kindly, trusting old man who set up the loan as only a semi-toothed debt...or debt having only limited recourse. That kindly old man had recourse, or legal teeth, to get back $5,000 of your principal and only 1/3 of the interest. If you didn't pay back anything else, then oh well, too bad for him. You took advantage of him, so you can celebrate not paying him back the money you promised.
How you sleepin' at night there, pal?