vindication.

From Late Middle English vendicacion, vyndicacion, vyndycacion (“assertion of a claim”), from Old French vindication (“revenge, vengeance”) (modern dialectal French vindication), or from Medieval Latin vendicātio, both from Latin vindicātiō (“avenging; defence, protection, vindication; punishment; etc.”), from vindicō (“to avenge; to take revenge on; to protect from; etc.”) + -tiō (suffix forming nouns from verbs, denoting processes, actions, or results of actions). Vindicō is derived from vindex (“claimant, vindicator; defender, protector”) + -ō (suffix forming regular first-conjugation verbs); and vindex from vim (the accusative singular form of vīs (“force; power, strength; etc.”), ultimately from Proto-Indo-European *weyh₁- (“to chase, pursue; to persecute; to suppress”)) + dīcere (the present active infinitive of dīcō (“to declare, state; to refer to; to say, talk; etc.”), ultimately from Proto-Indo-European *deyḱ- (“to point out, show”)). By surface analysis, vindicate + -ion (suffix denoting an action or process, or its result).