Lewis Short
(adjective) : carcĕrārĭus, a, um, id.
* Of or belonging to a prison: quaestus,of keeping a prison,Plaut. Capt. 1, 2, 20.—Hence, subst.: carcĕrārĭus, ii, m., a prisonkeeper, jailer, Inscr. Grut. 80, 5; Don. ad Ter. Phorm. 2, 3, 26; cf. carcer, I. C. b.
Charlton T. Lewis, Charles Short, A Latin Dictionary