To have sex with a Book, Article, or the Internet, and therefore reproducing its words but with your last name.
Plagiarism involves 5 key Stages:
Stage 1: John is assigned a term paper.
Stage 2: John goes to the Library.
Stage 3: John "Checks Out" a book.
Stage 4: John "Reads Between the Lines".
Stage 5: A few paper cuts later… His paper is written.
To sum it all up…
One night of fun equals a finished paper.