Be/go out like a light
phrase
To fall asleep quickly or suddenly.
After a long day at work, he went out like a light as soon as his head hit the pillow.
Often appears as...
- fall out like a light
- turned off like a light
Usage tips
Informal
Colloquial
phrase
To become unconscious suddenly or quickly.
He was hit so hard on the head that he went out like a light.
Often appears as...
- knock out like a light
- be out cold like a light
Usage tips
Informal
Idiomatic
phrase
To fall asleep quickly or suddenly.
After a long day at work, he went out like a light as soon as his head hit the pillow.
Often appears as...
- fall out like a light
- turned off like a light
Usage tips
Informal
Colloquial
phrase
To become unconscious suddenly or quickly.
He was hit so hard on the head that he went out like a light.
Often appears as...
- knock out like a light
- be out cold like a light
Usage tips
Informal
Idiomatic
Definition 1 of 2
Pro Tip 1/3Quick Sleep
Use it when describing someone falling asleep very fast, often from exhaustion.
After the triathlon, she went out like a light.
Pro Tip 2/3Colloquial Speech
It’s a casual expression, more suitable for informal conversations.
At sleepovers, my brother always goes out like a light.
Pro Tip 3/3Not Literal
The phrase is figurative, comparing quick sleep to turning off a light.
During the flight, most passengers were out like a light.
Pro Tip 1/3Quick Sleep
Use it when describing someone falling asleep very fast, often from exhaustion.
After the triathlon, she went out like a light.
Pro Tip 2/3Colloquial Speech
It’s a casual expression, more suitable for informal conversations.
At sleepovers, my brother always goes out like a light.
Pro Tip 3/3Not Literal
The phrase is figurative, comparing quick sleep to turning off a light.
During the flight, most passengers were out like a light.
Pro Tip 1/3Quick Sleep
Use it when describing someone falling asleep very fast, often from exhaustion.
After the triathlon, she went out like a light.
Pro Tip 2/3Colloquial Speech
It’s a casual expression, more suitable for informal conversations.
At sleepovers, my brother always goes out like a light.
Pro Tip 3/3Not Literal
The phrase is figurative, comparing quick sleep to turning off a light.
During the flight, most passengers were out like a light.
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