Mark Liberman at Language Log has come up with a term to describe one of the most idiotic plagiarism techniques I've ever heard of -- text laundering. The usual method is to save time and effort by copying someone else's work and submitting it as your own. But it's so easy to catch people doing that from online materials that some students are masking their trail by substituting words to fool Google, using a thesaurus to find synonyms and so on.
There are at least two problems with this (purely from the perspective of not wanting to get caught). One is that such use of a thesaurus is likely to lead to awkward enough sounding phrases that anyone reading it who is slightly informed will suspect something is up, and creative enough use of Google will easily find the source anyway. At least that's so unless the student is so thoroughgoing to be immune to Google, which would seem to be the point of text laundering. But such Google-proofing would take up so much time that the student might as well have learned enough of the material to begin with to write a competent essay just from class materials. Can you imagine how long it takes to replace every important keyword in a document one is plagiarizing with alternatives from a thesaurus, all of this after having combed Google for sources to begin with and spliced them together into a format that resembles an academic paper enough that they think it will fulfill the assignment? If plagiarizing is supposed to save time, and text laundering is supposed to make the time-saving effort harder to catch, there doesn't seem to be a good way to achieve both goals simultaneously.