Definition of "Addiction" :

noun: (Roman law) a formal award by a magistrate of a thing or person to another person (as the award of a debtor to his creditor); a surrender to a master

"Under Roman law addiction was the justification for slavery."

noun: an abnormally strong craving

noun: being abnormally tolerant to and dependent on something that is psychologically or physically habit-forming (especially alcohol or narcotic drugs)