Translation plagiarism is relatively a new term. It means that individuals copy the works of others as their own. Even when you take the written content and translate it from one language into another, it would also be a translation plagiarism.
We always use the word “ethical” if we want to describe something what is right, made or done according to rules and involves some moral values. Why then should we refer plagiarism to ethical issues too?
The term “plagiarism” has not existed till the 19th century, so it was quite difficult to accuse any writers of this crime. But now, when it is one of the most important issues in writing it is obvious, who cheated and presented works or ideas of other people as their own.