give a dog a bad name

It is very difficult to lose or change a bad reputation. A: "Ever since I failed my exam, my teacher sees me as a slacker, no matter what I do." B: "Well, give a dog a bad name, right?" It's so frustrating that everyone still sees me as the fool who traded my ace pitcher for next-to-nothing. "Give a dog a bad name," as they say! A: "Remember: you have to make a good first impression." B: "I know, 'give a dog a bad name' and all that."

give a dog a bad name

it is very difficult to lose a bad reputation, even if it is unjustified.

This is a shortened version of the proverb give a dog a bad name and hang him , which was known from the early 18th century.

give a dog a bad ˈname (and ˈhang him)

(saying) when a person already has a bad reputation, it is difficult to change it because others will continue to blame or suspect him/her