Plagiarism. Plagiarism means that you take someone else's work and present it as your own. This is the general case of cheating in an exam, where you might take your neighbour's work and present it as your own. It is just the same if you take a text off the internet, or from a book, and use it without clearly indicating where it came from. All such activity is intellectual theft.

Any plagiarism in a course is immediate grounds for failing that course, automatically.

Avoiding plagiarism is easy: you just put quote marks round what you have taken and cite the source, even if it's a web site.