What is another word for "jailer"?

Roget's Thesaurus (1911) lists these synonyms for "jailer": and, ayah, bodyguard, bonne, castellan, coast, concierge, costa, custodian, custos, duenna, escort, game, gaoler, governess, governor, guard, guardian, hayward, keeper, nanny, nurse, protector, ranger, sentinel, sentry, teacher, turnkey, ward, warder, watch, watchdog, watchman.