From Latin cui est bono? (“to whom is it a benefit?”).
- The principle that the ultimate initiator of an action is likely the person who stands to gain from the action.
1900, Evelyn Shuckburgh, Letters to Atticus, translation of original by Marcus Tullius Cicero:
- If the principle of cui bono is applied, it is evident that the gainers were the party of the trumvirs, whose popularity would be increased by a belief being created that their opponents the Optimates were prepared to adopt extreme measures to get rid of them.