A debt that isn't backed by collateral

Unsecured loans, like credit card debt, doctor bills and student loans, don't require you to sign an agreement pledging collateral, such as property, to secure the loan. If you fail to pay an unsecured loan, the creditor can only take you to court to get their money. Mortgages and car loans, though, are secured loans. So, in case of default, the lender can take back the collateral - the property or the car - and sell them to pay off the loan.

Compare: Mortgage, Deed of trust