1.
to ring (an alarm or alarm clock)
“My alarm goes off at 7 a.m.”
“The fire alarm went off.”
“Did your alarm go off this morning?”
Synonyms: to ring, to sound
Phrasal verb
What does go off mean?
Meaning: to ring (an alarm); to stop working (a light); to explode
B1
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Quick answer
Go off = to ring (an alarm). It can also mean to stop working (a light, the power), to explode (a bomb) or to go bad (food). My alarm went off at 7 = my alarm rang at 7. It has no object, and the context tells you the meaning.
Meanings of the phrasal verb
2.
to stop working (a light, the power, a machine)
common“The lights went off suddenly.”
“The heating goes off at midnight.”
Synonyms: to switch off, to stop working
3.
to explode (a bomb, fireworks)
common“The bomb went off at noon.”
“Fireworks were going off everywhere.”
Synonyms: to explode, to detonate
4.
to go bad (food), in British English
common“The milk has gone off.”
Synonyms: to spoil, to go bad
Word order
Intransitive (no object)
This phrasal verb does not take an object.
Forms
- Present Simple:
- go off
- Past Simple:
- went off
- Past participle:
- gone off
- -ing form:
- going off
Common mistakes to avoid
Go off or turn off?
Go off = to stop working by itself (no person does it). Turn off = to stop a machine on purpose (a person does it). The light went off (by itself) / I turned off the light (I did it).
One verb, two opposite meanings
Go off can seem strange: it means to ring (an alarm) AND to stop working (a light)! The context decides. The alarm went off = it started ringing. The lights went off = they stopped shining.
Practice quiz
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Related pages: go off
Pages on a similar topic or with a similar use, so you can keep exploring.
What's next?
Go off: you understand the rule. Now practise it.
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English contestGo off: often tested in the English contest
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Frequently asked questions
What does go off mean?+
Go off has 4 main meanings: (1) to ring (an alarm); (2) to stop working (a light); (3) to explode (a bomb); (4) to go bad (food, in British English). The context tells you which one it is.
How can go off mean both start and stop?+
It is a classic trap! With an alarm, go off means it starts ringing. With a light or a machine, it means it stops working. The alarm went off = it rang. The lights went off = they stopped shining.
What is the difference between go off and turn off?+
Turn off is something a person does on purpose: I turned off the TV. Go off happens by itself: the TV went off by itself. Turn off takes an object; go off does not.
What is the past simple of go off?+
Went off, because go is irregular. The fire alarm went off during the test = the fire alarm rang during the test.
Can go off mean to get angry?+
Yes, in informal English: go off at someone means to shout at someone angrily. He went off at me for being late = he got angry with me because I was late. This is a less common meaning.
Updated on 12 November 2026 by the Big Challenge teaching team. Every year, more than 500,000 students across Europe take part in our English contest, created in 1999. Our teaching approach →
The Big Challenge · Updated on 12 November 2026 · Source: www.thebigchallenge.com/bl/academy/learn-english/phrasal-verbs/go-off
© The Big Challenge. Copying allowed for classroom use. Every year, more than 500,000 students across Europe take part in our English contest, created in 1999.