What Is Meant By Plagiarism?

Plagiarism is a term used to define the unauthorized copying of any material and is considered a serious offense. It is expressing someone else's thoughts as your own. For detail visit Plagiarism.

There are different types of plagiarism: Complete plagiarism, near complete plagiarism, patchwork plagiarism, lazy plagiarism and even self-plagiarism. Referring to Wikipedia, the definition of plagiasm is:

Plagiarism is the "wrongful appropriation" and "stealing and publication" of another author's "language, thoughts, ideas, or expressions" and the representation of them as one's own original work.

Plagiarism is considered academic dishonesty and a breach of journalistic ethics. It is subject to sanctions like penalties, suspension, and even expulsion. Recently, cases of "extreme plagiarism" have been identified in academia. The modern concept of plagiarism as immoral and originality as an ideal emerged in Europe in the 18th century, particularly with the Romantic movement.

Here's a great blog dedicated to the problem of detecting plagiarism https://plagtools.com/ , I highly recommend reading it.

That something was in violation of copywrite laws. In school its using someone's work as you own. Which is just cheating your self.