A person employed to keep watch for some anticipated event.

synonyms: lookout, lookout man, picket, scout, sentinel, spotter, watch.

Roget 664: safety, security, surety, impregnability; invulnerability, invulnerableness etc. adj.; danger past, danger over; storm blown over; coast clear; escape etc. 671; means of escape; blow valve, safety valve, release valve, sniffing valve; safeguard, palladium.    guardianship, wardship, wardenship; tutelage, custody, safekeeping; preservation etc. 670; protection, auspices.    safe-conduct, escort, convoy; guard, shield etc. (defense) 717; guardian angel; tutelary god, tutelary deity, tutelary saint; genius loci.    protector, guardian; warden, warder; preserver, custodian, duenna [Sp.], chaperon, third person.    watchdog, bandog^†; Cerberus; watchman, patrolman, policeman; cop [Slang], dick [Slang], fuzz [Slang], smokey [Slang], peeler [Slang], zarp [Slang]; sentinel, sentry, scout etc. (warning) 668; garrison; guardship^†.    [Means of safety] refuge &c., anchor etc. 666; precaution etc. (preparation) 673; quarantine, cordon sanitaire [Fr.].    [Sense of security]. confidence etc. 858 ... show more

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

Dutch: wacht, schildwacht, uitkijk, verkenner
Polish: wartownik