Repeat something you've read or heard precisely word-for-word, and you have just quoted it verbatim. That's great if what you deliver verbatim is the directions on how to defuse a bomb, but not a good idea if you're cheating on a test and copying someone's answer verbatim.
As a word, verbatim is powerful for its precision. When you can say that you are repeating someone's words verbatim, it means every single word is exactly what was said. If you write something down verbatim, you can rely on it being a duplicate of the original document, recreated. Repeating words verbatim in your own writing can be tricky business. Without attributing the original author, verbatim can be the damning evidence of plagiarism.