warder(n = noun.person) - a person who works in a prison and is in charge of prisoners;
is a kind of law officer, lawman, peace officer
has particulars: wardress
Derived forms verb ward₁, noun wardership₁

1.  One who wards or keeps; a keeper; a guard. Dryden. [1913 Webster]

2.  A truncheon or staff carried by a king or a commander in chief, and used in signaling his will. [1913 Webster]
"When, lo! the king suddenly changed his mind,
Casts down his warder to arrest them there." [1913 Webster]
"Wafting his warder thrice about his head,
He cast it up with his auspicious hand,
Which was the signal, through the English spread,
This they should charge." [1913 Webster]

warder, n.
1 Brit. (fem. wardress) a prison officer.
2 a guard.

Etymology:
ME f. AF wardere, -our f. ONF warder, OF garder to GUARD

N  safety, security, surety, impregnability, invulnerability, invulnerableness, danger past, danger over, storm blown over, coast clear, escape, means of escape, blow valve, safety valve, release valve, sniffing valve, safeguard, palladium, guardianship, wardship, wardenship, tutelage, custody, safekeeping, preservation, protection, auspices, safe-conduct, escort, convoy, guard, shield, guardian angel, tutelary god, tutelary deity, tutelary saint, genius loci, protector, guardian, warden, warder, preserver, custodian, duenna, chaperon, third person, watchdog, bandog, Cerberus, watchman, patrolman, policeman, cop, dick, fuzz, smokey, peeler, zarp, sentinel, sentry, scout, garrison, guardship, refuge &c, anchor, precaution, quarantine, cordon sanitaire, confidence, protect, take care of, preserve, cover, screen, shelter, shroud, flank, ward, guard, secure, entrench, intrench, fence round, house, nestle, ensconce, take charge of, escort, convoy, garrison, watch, mount guard, patrol, make assurance doubly sure, take up a loose thread, take precautions, double reef topsails, seek safety, take shelter, find shelter, Adj, safe, secure, sure, in safety, in security, on the safe side, under the shield of, under the shade of, under the wing of, under the shadow of one's wing, under cover, under lock and key, out of danger, out of the woods, out of the meshes, out of harm's way, unharmed, unscathed, on sure ground, at anchor, high and dry, above water, unthreatened, unmolested, protected, cavendo tutus, panoplied, snug, seaworthy, weatherproof, waterproof, fireproof, defensible, tenable, proof against, invulnerable, unassailable, unattackable, impenetrable, impregnable, imperdible, inexpugnable, Achillean, safe and sound, scathless, unhazarded, not dangerous, unthreatening, harmless, friendly (cooperative), protecting, protective, guardian, tutelary, preservative, trustworthy, ex abundanti cautela, with impunity, all's well, salva res est, suave mari magno, a couvert, e terra alterius spectare laborem, Dieu vous garde.

N  keeper, custodian, custos, ranger, warder, jailer, gaoler, turnkey, castellan, guard, watchdog, watchman, Charley, chokidar, durwan, hayward, sentry, sentinel, watch and ward, concierge, coast guard, guarda costa, game keeper, escort, bodyguard, protector, governor, duenna, guardian, governess, nurse, nanny, babysitter, catsitter, dogsitter, bonne, ayah.

N  perforator, piercer, borer, auger, chisel, gimlet, stylet, drill, wimble, awl, bradawl, scoop, terrier, corkscrew, dibble, trocar, trepan, probe, bodkin, needle, stiletto, rimer, warder, lancet, punch, puncheon, spikebit, gouge, spear, puncher, punching machine, punching press, punch pliers.

N  stopper, stopple, plug, cork, bung, spike, spill, stopcock, tap, rammer, ram, ramrod, piston, stop-gap, wadding, stuffing, padding, stopping, dossil, pledget, tompion, tourniquet, cover, valve, vent peg, spigot, slide valve, janitor, doorkeeper, porter, warder, beadle, cerberus, ostiary.