# light a fire under

idiom

Source: https://englishreference.com/idiom/light-a-fire-under
Updated: 2026-08-10

## Meaning

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

## Examples

- The deadline is close, so I need to light a fire under my team.
- I need to light a fire under myself to finish this project today.
- Our manager lit a fire under the sales department after profits dropped last quarter.
- You should light a fire under the landlord because the leaking pipe in the kitchen is getting worse every day.
- The threat of a heavy fine usually lights a fire under people to pay their taxes on time.
- The coach's harsh words at halftime finally lit a fire under the players, who returned to the field with a desperate energy that turned the game around.

## Origin

The idiom refers to the practice of compelling chimney sweeps to complete their ascent. When a sweep, typically a young boy, hesitated or became stuck within a narrow flue, a fire was lit in the hearth below to provide the necessary motivation to reach the top. The rising heat and smoke ensured that remaining stationary was no longer a viable option, effectively aligning the sweep’s professional interests with his immediate survival.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.