Here's why:
* Copyright: Dictionary definitions are protected by copyright. While the basic idea of a word's meaning is not copyrightable, the specific wording and phrasing used to express that meaning are.
* Academic Integrity: Even if you don't explicitly cite the dictionary, using its exact wording without attribution implies that the work is your own, which is dishonest.
* Lack of Originality: Copying a definition directly does not demonstrate any original thought or understanding of the concept.
What to do instead:
* Use your own words: Read the definition and then paraphrase it in your own words, ensuring you understand the meaning fully.
* Cite your source: If you must use the exact wording, clearly cite the dictionary you are using.
* Use multiple sources: Consult different dictionaries and resources to get a comprehensive understanding of the word and create a unique definition.
Remember, plagiarism is a serious academic offense that can have consequences. Always strive to be original in your writing and properly attribute any sources you use.