Red light
WordNet
noun
(1) The signal to stop
(2) A cautionary sign of danger
WiktionaryText
Noun
- A warning light, especially as a traffic signal indicating ‘stop’.
- We ran three red lights on the way to the hospital.
- A sign of a brothel.
- 1978: Roxanne, you don't have to put on your red light. — Sting, ‘Roxanne’
- Denial to proceed. Ruling out of any possibility.