Someone who guards prisoners.

synonyms: gaoler, jailor, prison guard, screw, turnkey.

Roget 753: keeper, custodian, custos [Lat.], ranger, warder, jailer, gaoler, turnkey, castellan^†, guard; watchdog, watchman; Charley; chokidar^†, durwan^†, hayward^†; sentry, sentinel; watch and ward; concierge, coast guard, guarda costa [Sp.], game keeper.    escort, bodyguard.    protector, governor, duenna [Sp.]; guardian; governess etc. (teacher) 540; nurse, nanny, babysitter, catsitter, dogsitter, bonne [Fr.], ayah^†.    ... show more

Roget 975: scourge, rod, cane, stick; ratan^†, rattan; birch, birch rod; azote^†, blacksnake^†, bullwhack [U.S.], chicote^†, kurbash^†, quirt, rawhide, sjambok^†; rod in pickle; switch, ferule, cudgel, truncheon.    whip, bullwhip, lash, strap, thong, cowhide, knout; cat, cat o'nine tails; rope's end.    pillory, stocks, whipping post; cucking stool^†, ducking stool; brank^†; trebuchet^†, trebuket^†.    [instruments of torture: list], triangle, wooden horse, iron maiden, thumbscrew, boot, rack, wheel, iron heel; chinese water torture.    treadmill, crank, galleys.    scaffold; block, ax, guillotine; stake; cross; gallows, gibbet, tree, drop, noose, rope, halter, bowstring; death chair, electric chair; gas chamber; lethal injection; firing squad; mecate^†.    house of correction etc. (prison) 752.    goaler, jailer; executioner; electrocutioner^†; lyncher; hangman; headsman^†; Jack Ketch.    ... show more

Dutch: gevangenbewaarder, cipier
Polish: strażnik więzienny