retainer

From retain + -er. retain comes from Late Middle English reteinen, retein (“to continue to keep, retain; to continue to possess; to possess; to contain; to draw back, retire; to hold back, restrain; to keep in mind, remember; to take back, repossess; to appoint; to engage in one’s service, employ, hire”)retainen, retayne, reteign, reteigne, reteine, retene, retenne, reteyene, reteygn, reteygne, reteyign, reteyn, reteyne, retine, from Anglo-Norman reteiner, retenirrestenir, reteigner, reteingner, retener, retenier, retiner, Middle French retenir, and Old French retenir (“to keep back, retain; to keep, maintain, preserve; to possess; to engage in one’s service, employ; to detain; to hold back, restrain; to remember”) (modern French retenir), from Vulgar Latin retino, from Latin retinēre, the present active infinitive of retineō (“to keep or hold back, detain, retain; to hold in check, stop; to hold fast, maintain; to keep in mind, remember”) (compare Latin retineō (“to keep engaged in one’s service”)), from re- + teneō (“to grasp, hold; to hold fast, restrain; to possess; to keep in mind, remember”) (ultimately from Proto-Indo-European ten- (“to extend, stretch”)). Christianity (“to declare (a sin) not forgiven”) is derived from John 20:23 in the Bible, in Late Latin quorum retinueritis, retenta sunt, and in Koine Greek ἄν τινων κρατῆτε, κεκράτηνται: see the 1526 quotation. 2

Etymology from Wiktionary, CC BY-SA