1 B1 informal
To ignite a firework, rocket, or explosive device, causing it to fire or launch.
"The kids were excited to light off the fireworks after it got dark."
separable
light off
B2 informal separable transitive/intransitive
To ignite or fire something, such as a firework or rocket; also, to depart quickly.
In plain English
To set something on fire to make it launch or explode, like a firework — or to leave fast.
What does "light off" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 C1 idiomatic informal
To leave suddenly or quickly (dialectal/archaic).
"He lit off down the road before anyone could ask him any questions."
Literal vs figurative
Words literally mean
To apply a light (flame) so that something fires off — fairly transparent.
Actually means
To set something on fire to make it launch or explode, like a firework — or to leave fast.
Usage tip
Chiefly American English. In the sense of igniting fireworks or rockets, it is common in informal speech. The sense of departing quickly is dialectal and less common. Not to be confused with 'light up'.
Words that pair with "light off"
Natural word combinations native speakers use most often.
firework rocket firecracker flare fuse
How to conjugate "light off"
The five tense forms you'll use most often.
Base
light off
I/you/we/they
3rd person
lights off
he/she/it
Past simple
lighted off
yesterday
Past participle
lighted off
have + pp
-ing form
lighting off
continuous
Hear "light off" in the wild
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Other ways to say "light off"
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