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Related to go bad: Go bag
1. To spoil, as of food or drink. Based on the awful smell, I'm pretty sure that meat has gone bad.
2. To become unpleasant or unfavorable. They always seem so annoyed with each other anymore—I bet their relationship has gone bad.
3. To begin to engage in lawlessness. I'm really worried that my son will go bad if he keeps hanging out with that group of troublemakers.
to become rotten, undesirable, evil, etc. I'm afraid that this milk has gone bad. Life used to be wonderful. Now it has gone bad.
Spoil, decay; also, turn to crime. For example, You can tell from the smell that this milk has gone bad, or If he keeps running around with that street gang, he's sure to go bad. [Late 1800s]