"secured" means that when someone gives you the cash, you sign a piece of paper saying that if you are unable to pay back the loan, the lender has the right to take the asset on which the loan was "secured" and sell it to pay off the loan.

Normally loans are secured on a house, but it can be anythign of vaue that can be easly sold to pay of the loan if the borrower becomes unable to pay.

Unsecured is simply the opposite. There is no link between the loan amount and any specific asset.

When you take money from Big Shuggy, you loan is "secured" on you knees.