vanquishEnglishOxford Dictionary of Englishvanquish /ˈvaŋkwɪʃ / ▸ verb [with object] literary defeat thoroughly: he successfully vanquished his rival. – DERIVATIVES vanquishable /ˈvaŋkwɪʃəbl / adjective– ORIGIN Middle English: from Old French vencus, venquis (past participle and past tense of veintre), vainquiss- (lengthened stem of vainquir), from Latin vincere ‘conquer’.