go off

If a light or a machine goes off, it stops working:
The lights went off in several villages because of the storm.
The damage to the fuse box caused the power to go off.
The light goes off when the batteries are flat.
The match had to be abandoned when the floodlights went off.
The electricity will be going off for ten minutes while the workmen test the circuit.
It's getting cold. The heater must have gone off.

If a bomb goes off, it explodes:
The bomb went off at midday.

If a gun goes off, it fires:
His gun went off accidentally.

UK
If food or drink goes off, it is not good to eat or drink any more because it is too old:
This bacon smells a bit funny - do you think it's gone off?

If a warning device goes off, it starts to ring loudly or make a loud noise:
The alarm should go off automatically as soon as smoke is detected.
Didn't you hear your alarm clock going off this morning?

to leave a place and go somewhere else:
She's gone off on holiday with Tony.

to happen in a particular way:
The protest march went off peacefully.

UK
to become worse in quality:
That paper's really gone off since they got that new editor.
(Cambridge Advanced Learner's Dictionary & Thesaurus からの go off の定義 © Cambridge University Press)

アメリカ英語辞典
to explode, or to fire bullets:
The deer ran away just before the hunter’s gun went off.

If a special signal or an electronic device goes off, it warns people that there is danger or that something is wrong:
What do they do if the metal detector goes off?
(Cambridge Academic Content Dictionary からの go off の定義 © Cambridge University Press)

- Cambridge Dictionary