I don’t understand what the problem here is actually. If you plagiarize on an assignment for school, that’s bad, because the goal of assignments is to test your knowledge and plagiarism makes it a less effective test. But here the goal (I think) is to produce an informative and accurate paper. You told them the definition - what would have been gained by rephrasing the definition you told them? Especially if they’re nonnative english speakers, it seems likely that any rephrasing would have made the definition less understandable and possibly less accurate.
I guess the fear is that they don’t actually understand the definition, and anyone reading the paper will incorrectly believe that they do, improving their reputation in a way they don’t deserve?
I guess the fear is that they don’t actually understand the definition, and anyone reading the paper will incorrectly believe that they do, improving their reputation in a way they don’t deserve?