Translation guide
How to express turning off a device, light, or engine in Japanese, with attention to transitive/intransitive pairs and natural phrasing.
You want to say that someone turns off a device, light, or appliance.
The most common verb for turning off lights, TVs, and other electronic devices. Transitive.
電気を消してください。
Please turn off the light.
I turned off the TV.
Used for turning off devices by cutting power, often with a switch. Common for engines and some appliances. Transitive.
Please turn off the air conditioner.
Turn off the engine.
Loanword expression meaning 'to turn off'. Common for electronic devices and settings.
Please turn off your smartphone.
You want to say that a device or light turns off by itself or automatically.
Intransitive counterpart of 消す. Used when a light or device goes off on its own.
Suddenly, the light went off.
The TV turned off by itself.
Intransitive counterpart of 切る. Used when power is cut or a device stops, often due to a timer or malfunction.
Specifically for stopping a car, motorcycle, or machine engine.
Informal, figurative use meaning to stop concentrating or disengage.
消す is the default for lights, TVs, and most electronics. 切る is used for cutting power or stopping engines. For many devices, both are possible, but 消す is more common in daily life.
Turn off the light (both possible, 消す is more natural)
The direct loanword 'スイッチオフ' is not commonly used as a verb. Use 消す or 切る instead.
エアコンが自動で切れた。
The air conditioner turned off automatically.