Most assuredly not a German word, as asserted by the douchebags previous to me. Shiza, literally, means nothing in German, as in - of course - that it holds no meaning. Saying "shiza" to a German person will warrant you an odd look, and possibly an insult.
(Dip shit) SHIZA! SHIZA!
(Reasonable person) Shut up, fucktard; that's not an actual word in any language, at least not in the context in which you use it.