(n.) A man whose business is to manage or display signals; especially, one employed in setting the signals by which railroad trains are run or warned.

Druid Eeyore Jeremiah admonisher astrologer augur calamity howler cautioner crepehanger crystal gazer cynic defeatist divinator diviner divineress flagman forecaster foreknower foreseer foreshower foreteller fortuneteller geomancer haruspex killjoy lighthouse keeper lookout lookout man malist monitor negativist nihilist palmist pessimist predictor prefigurer presager prognosticator prophesier prophet prophet of doom prophetess psychic pythoness religious prophets retreatist seek-sorrow seer seeress sentinel sentry signaler signalman soothsayer vates warner weather prophet worrywart