(3 syl.), to justify, to avenge, has a remarkable etymon. Vindicius was a slave of the Vitelli, who informed the Senate of the conspiracy of the sons of Junius Brutus to restore Tarquin, for which service he was rewarded with liberty (Livy, ii. 5); hence the rod with which a slave was struck in manumission was called vindicta, a Vindicius rod (See Manumit ; and to set free was in Latin vindicare in libertatem. One way of settling disputes was to give the litigants two rods, which they crossed as if in fight, and the person whom the praetor vindicated broke the rod of his opponent. These rods were called vindiciae, and hence vindicate, meaning to “justify.” To avenge is simply to justify oneself by punishing the wrongdoer.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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