Definition of idiot light in English:

idiot light

noun

North American
informal
  • A warning light that goes on when a fault occurs in a device.

    • ‘The idiot light for Foxtrot Base just turned red; they are surrounded.’
    • ‘Other than this high-tech version of a car's idiot light, I saw no other symptoms.’
    • ‘While I waited I scanned my HUD and checked the idiot lights from the other stations on my watch; all were green; no one was under attack.’
    • ‘An apt metaphor indeed, as motor mechanics call these gizmos ‘idiot lights.’’
    • ‘For providing an easy-to-use ‘security idiot light’ to Linux system administrators and distributions everywhere, Nmap, we salute you.’