idiot light

In real, traceable use. Part of the curated seed collection; community review is coming.

Meaning · English

Any warning light or indicator on the dashboard of a car, designed to alert the driver to problems, such as the parking brake being on or the oil being low.

Register: slang

Where it’s used: Used American English
Sources & notes

Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).

Common questions

What does “idiot light” mean?

Any warning light or indicator on the dashboard of a car, designed to alert the driver to problems, such as the parking brake being on or the oil being low.

Is “idiot light” formal or informal?

idiot light is generally slang.