go out like a light
US /ɡoʊ aʊt laɪk ə laɪt/
UK /ɡoʊ aʊt laɪk ə laɪt/
1.
to fall asleep very quickly or suddenly
:
•
After working all day, he went out like a light as soon as his head hit the pillow.
•
The baby was so tired that she went out like a light during her feeding.
2.
to lose consciousness suddenly
:
•
The boxer took a heavy punch and went out like a light.
•
The sudden drop in blood pressure made her go out like a light.