Plagiarism can take many forms but can generally be considered as being accidental or deliberate:
Accidental plagiarism is where there is no deliberate intention on your part to 'cheat'.
Accidental plagiarism could occur, for example, if you copy some text into your essay from an academic text, but forget to cite it, or do not know that you need to cite it. This is more likely to happen if you are a new student, but could indicate poor academic writing skills at any level of study.
To avoid committing accidental plagiarism, you should seek guidance in academic writing and referencing skills to check you are referencing correctly.
Deliberate plagiarism is where there is actual intent on your part to 'cheat'.
Here are three examples of deliberate plagiarism:
Copying from published material – for example an assessment submission may contain occasional deliberate cutting and pasting from the internet without adequate referencing. This may also be accidental, as a result of poor academic writing skills, but is always viewed as plagiarism.
Outright deception – examples here include submitting work that has been purchased from a “cheat site” or otherwise written by someone else, and submitting it as your own. This includes collusion between one or more students.
Self plagiarism – here a student deliberately submits the same piece of work for more than one assignment. If the guidelines for two assignments are similar, you are still required to write a new assignment each time. If you submit an old essay for a new assessment, it is still plagiarism, even though you are plagiarising yourself.