To act as an arbitrator; to settle a dispute or make a judgment between two parties.
From Old French arbitrer (to judge, decide), derived from Latin arbitrāri (to watch, judge, decide). The verb form evolved naturally in English to describe the action of arbitrating.
Arbitrer is a less common verb today—we usually say 'arbitrate' instead. But it shows how English verbs can stay in different forms: arbitrate (common modern form) and arbitrer (historical variant) both mean the same thing, like how we have 'memorize' and the older 'memorise' in British English.
Complete word intelligence in one call. Free tier — 50 lookups/day.