# light a fire under

> English word · Verb

## Definitions
1. To motivate or encourage (someone) to start sooner or move faster.

## Etymology
Referring to a time when, if chimney sweeps were afraid to ascend a chimney, the fire would be lit under them in order to motivate them to climb to the top.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-09-03.
Canonical page: https://plainspell.com/en/word/light-a-fire-under