Plagiarism is defined as taking credit for work or ideas that are not one's own by wrongfully copying or stealing another's language, thoughts, or expressions and representing them as original work. The document discusses how plagiarism is stealing another's effort and credit, which is unfair to the original creator. It provides tips to avoid plagiarizing such as keeping work safe, reporting acts of plagiarism, and not letting others copy one's work. In conclusion, the document states plagiarism should not be permitted or rewarded as it is seriously unfair to those who put in real effort and work.