A name you give to someone for comitting plagiarism excessively and posting other peoples songs or videos on their blog without giving the original artists credit.
Person 1: "I downloaded that song I showed you the other day and posted it on my Newgrounds profile without giving the artists credit!"

Person 2: "Wow, you're a bit of a Mathum aren't you?"
by David Stead January 26, 2009
Get the Mathum mug.