Noun
(rail transport) A signal set at danger and showing a red light or other stop indication, which a train driver must not pass until it changes or until manually cleared past the signal by a dispatcher.
(also figurative) An indication that a potentially bad or dangerous situation could develop.
danger-signal (plural danger-signals)
Alternative spelling of danger signal.
danger-signal
A good bachelor drinks his dessert (and sometimes the rest of his meals). A sweet tooth is a danger signal that you're getting too much exercise and not enough cocktails. P. J. O'Rourke