Plagiarism

Unethical. - when you use someone's words, information, and idea and you don't acknowledge that it is thier work.
Means a lot of lost learning opportunity. - instructors assign research assignments to help students learn how to make a proper research paper. It helps the student gain knowledge through experience
Diminishes your credibility - stealing other peoples ideas in alright when you are writing a research paper, but you have to give the author credibility. You can do this by properly citing the ideas and words from other authors.
It may result in serious penalties. - all schools do not accept any form of plagiarism. The penalties for it are suspension or even expulsion . It is not taken lightly, and it is something that will follow you throughout the rest of your career.