Go off means to suddenly make a loud noise or start ringing (an alarm, an alarm clock), to explode or fire (a gun, a bomb), and to spoil or become bad (food). Which meaning applies depends on the subject: the alarm went off — the alarm started ringing; the milk has gone off — the milk has spoiled. The 'spoil' meaning is mainly British; American English tends to say go bad instead.
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go off (alarm/gun/bomb); go off (food, milk, meat)
- The fire alarm went off in the middle of the night and woke everyone up.
- Don't drink that milk — it's gone off.
- My phone alarm didn't go off, so I was late for work.
What changed
First versionA car alarm worked at 3 a.m. and woke up half the street.
RevisionA car alarm went off at 3 a.m. and woke up half the street.
Work seems like the obvious choice for describing an alarm doing its job, but an alarm that works simply means it's in good order and functioning correctly: Our alarm works fine. When an alarm or alarm clock suddenly starts ringing, the phrase is go off: a car alarm went off.
Turn off means to switch something off yourself: Can you turn off the alarm? Go off happens on its own. With lights and electricity, it means 'to stop working, to go out', not 'to start ringing': The lights went off during the storm — the power failed during the storm.
Your turn
I forgot to put the fish in the fridge, and by morning it had completely ___.
Show the answer
gone off — The fish was left out of the fridge overnight and had clearly spoiled by morning — gone off. Gone down doesn't make sense here: it's about something decreasing or falling, not food spoiling.
Describe a case involving an alarm or alarm clock, or food that went off. Say exactly what happened and when.
The smoke alarm went off at six this morning because my flatmate burnt the toast.
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