The German word Scheisse, which means "shit."

Yes, from German, probably via Yiddish.

1) "The origin is mostly likely from German Scheißer ("incompetent worthless person,"), from scheißen (“to defecate”)." Source and further information: http://en.wiktionary.org/wiki/shyster "The online dictionaries I've consulted specify the word's origin in medieval German, not Yiddish. I'd like to see more proof of its derivation in Yiddish before I'd include this here as fact." http://en.wiktionary.org/wiki/Talk:shyster "The word is derived from the German verb scheissen, "to defecate" and the English suffix -ster, "one who does". Shyster is an alteration of the German scheißer, which literally means "defecator" or an "incompetent worthless person"." Source and further information: http://en.wikipedia.org/wiki/Shyster (Categories: Yiddish words and phrases) "Shyster: Unscrupulous person." Source and further information: "Glossary of Yiddish and Hebrew Terms" http://www.awordinyoureye.com/Glossary.html 2) "Shyster is derived from the German word scheisser, which means defecator or shitter. Shyster may sound like a Yiddish word, but it isn’t. I grew up in a Jewish neighborhood, where I learned The Joys of Yiddish. Growing up, I sometimes heard kucker, which is the Yiddish word for shit head" Source and further information: http://rivervices.blogspot.com/2008/07/american-dreams-american-nightmares.html 3) "The true story of the passage of the term "shyster" into the language has its origins in the journalistic ravings of Mike Walsh, a man alternately described as a political radical, a visionary, a crusader for lost causes, a demagogue, and a drunk." ""Ven you put sich pieces as that 'ere in the paper," Terhune admonished Walsh in his apparently German brand of English, "you ought to make the exceptions — ought to lay it down straight — you understand. There's plenty of 'em around [the Tombs] that wants [publicity for their misdeeds] — wants all you can give 'emi hut ven you do it, just give the names, so I won't be confounded with sich shiseters as Magee, Peck, Camp, and Stevenson, because I'm down on sich suckers as them — I am." Terhune went on to provide a definition of the previously unheard of term "shiseter", it involved the word's relationship to the German words "scheisse," the equivalent of "shit" in English, and "sheisser," meaning someone of no worth. Walsh loved the word, which he bastardized into "shyster," but did not begin to use immediately. For most of the summer of 1843 Walsh made no mention of Terhune's term. Then, in September, Walsh was charged with eleven counts of libel resulting from articles he had written in the Subterranean. Angered, Walsh reached deep into his bag of pejorative terms for lawyers and came up with "shyster." At first the word showed up twice in the same issue, then, the next week after that, Walsh used "shyster" eleven times in one issue." "Cohen spent some five or six years sorting through the twelve different theories of the origin of the word "shyster" which, prior to his effort, prior to his effort, comprised one of the great etymological swamps and mysteries of all time. In addition to disproving Moss's Scheuster story, Moss argues through the following hypotheses: that shyster derived from the Gaelic "siostair" (barrator); that shyster was the result of the combination of "shy" (either from "Shylock" or from "shy," meaning disreputable) with "-ster," a one-size-fits-all derogatory suffix: or that shyster came from the Dutch, from Yiddish, or from Gypsies" Source and further information: "Accidentally, on Purpose By Ken Dornstein" http://books.google.com/books?id=PyM9tR1jBPoC&pg=PA407&lpg=PA407&dq=shyster+Yiddish&source=bl&ots=Ck5zFT03Gp&sig=LVLnFAR2g0zHX9fSdwx2aRk08AA&hl=en&ei=GRHNSZqxDZOJsAb2j7imCA&sa=X&oi=book_result&resnum=3&ct=result