Definition
This idiom describes a situation where a person's past negative behavior or reputation makes it difficult for them to be viewed differently, as people tend to expect them to continue behaving badly.
He got a bad name from the mistakes he made when he was young, and now it's very difficult for him to find a job; it's really a case of 'give a dog a bad name'.
The company 'got a bad name' due to several scandals in its early days, and even though they have tried to improve, customers still don't trust them.
The media has constantly reported negative news about him, it's as if they 'gave a dog a bad name,' and now everything he does is criticized.