1. To be discharged or activated
2. To happen in a particular manner; SYN. come off, go over.
3. To stop running, functioning, or operating, as of power.
4. When a gun goes off, it fires. When a bomb goes off, it explodes. When an alarm or alarm clock goes off, it makes a loud noise.
5. When an electrical device or system goes off, it stops operating. Come on is the opposite of go off.
6. When an event or plan goes off well, smoothly, without a problem, or without a hitch (a hitch is a problem), it happens as planned.
7. When a road, trail, path, and so on, goes off, it leaves the main road, trail, or path, and goes in a different direction.