Final answer:
Plagiarism involves presenting someone else's work as your own, and it is both unethical and illegal. It can result in severe consequences.
Step-by-step explanation:
Plagiarism is the act of presenting someone else's work as your own, which is not only unethical but also illegal. It includes various forms such as copying someone else's paper or work without giving proper credit, submitting a paper written by someone else as your own, or even unintentionally copying information without proper attribution. Plagiarism can have serious consequences, including academic penalties and damage to one's reputation.