nexum, in very early Roman law, a type of formal contract involving the loan of money under such oppressive conditions that it might result in the debtor’s complete subjection to the creditor. The transaction was accomplished by means of a ritual employing scales and copper, the traditional symbols of transfer of property. The procedure was discontinued in the late 4th century bc, when the so-called Lex Poetelia released all those who were nexi (i.e., insolvent debtors held in bondage by their creditors).