Plagiarism is essentially the copy-and-paste-ing of someone else's words as your own, generally more than 3 words in a row, without attribution. For example, from What Is Plagiarism? | Poorvu Center for Teaching and Learning
Unless the original author is a Republican. Further:Plagiarism is the use of another’s work, words, or ideas without attribution. The word “plagiarism” comes from the Latin word for “kidnapper” and is considered a form of theft, a breach of honesty in the academic community. Plagiarizers suffer serious consequences in Yale College—including suspension or expulsion from school. (See the Yale College Undergraduate Regulations for more information.)
The concept of "Fair Use" is in opposition to plagiarism, and you must be clear on which one you're doing. Fair use - WikipediaIt may be difficult to think of yourself as making an original contribution in the context of a class taught by an expert. But every assignment is an invitation to add something new to the conversation sparked by the course. You cannot make an original contribution if you are not the owner of the words and ideas that you present.
Note that in both cases I have cited the source, and have not used their entire text under that citation. I have used their prose to present the idea, I have attributed it to them, but I have not used so much of the content as to make it unnecessary to refer to the original text.The fair use right is a general exception that applies to all different kinds of uses with all types of works. In the U.S., fair use right/exception is based on a flexible proportionality test that examines the purpose of the use, the amount used, and the impact on the market of the original work.
You may use our concepts, and we hope you do, but take care not to present them as your own.