Against; conflicting; opposite.
A contra-balance is the amount in an account of a creditor that is the opposite of the usual balance of such an account. It is an account receivable (a debt owed to the creditor) but with a credit balance (an amount owed to the debtor greater than what is owed to the creditor). The creditor therefore owes the debtor money, the opposite of the normal debtor-creditor relationship.
adj. Latin for against or opposite to. This usage is usually found in legal writing in statements like: "The decision in the case of Hammerhead v. Nail is contra to the rule stated in Keeler v. Beach."
CONTRA. Over; against; opposite to anything: as, such a case lays down a certain principle; such other case, contra.