the "wrongful appropriation," "close imitation," or "purloining and publication" of another author's "language, thoughts, ideas, or expressions," and the representation of them as one's own original work, but the notion remains problematic with nebulous boundaries.In simple terms, copying stuff from others and presenting it as your own is plagiarism. It is taken very seriously in this world.
Plagiarism is wrong. The very thought of copying someone else's work and presenting it as your own should be considered un-ethical. Although it is not a crime, plagiarism is something taken rather seriously these days- and that is why you should be careful.
That being said, everyone is a plagiarist. At some point of your life, you have copied stuff to complete your work- admit it.
The point is to make sure you hide your sources well. And that, unfortunately, is the truth. Every idea must have been generated from some crude thought, which you must have picked up from somewhere.
Back to the point of this post- how to get away with it? If you have copied your whole thesis, or a full design, even God Himself can't save you. Here's how it works.
If you have a copied image from somewhere, all you need to do is search it using Google images and viola! The source would be right in front of you. If you have copied a text (paragraph, definition, article), all you need to do is search it (a sentence preferably) under double quotes, and the source would be right there in front of you! In fact, this job has been simplified further by websites such as these (http://www.dustball.com/cs/plagiarism.checker/) which does the search for you.
If you are submitting anything handwritten, don't even bother about plagiarism- no one the time to type it and check it out. That being said, I guess you can get away with it if you put your ideas and the online stuff together. Try and change the text at relevant places so that a search under the parenthesis doesn't yield a proper result.
Other than that, I would rather not complete that work rather than copy paste it from a random source.