1. having full power: invested with complete authority to act independently
2. conferring full power: giving the holder complete authority to act independently
noun (pluralplen·i·po·ten·ti·ar·ies)
Definition:
official with full powers: an ambassador, envoy, or delegate invested with full authority to act or negotiate independently on behalf of a government or sovereign
[Mid-17th century. < medieval Latin plenipotentiarius< late Latin plenipotent- "having full power" < plenus "full" + potent- "powerful"]