Eugene Volokh asks: "Amuck or amok" -- which is the prefered spelling?
He quite sensibly and correctly writes: "Amuck or amok?, asks a reader, responding to an earlier post. The answer, as is often the case with such linguistic issues, is that both are acceptable, as dictionaries make clear. A google search suggests that "amok" is more common, though "amuck" is common enough; a NEXIS search is unhelpful, because it quite reasonably treats the two as synonyms, so that a search for either finds both. The word comes from Malay, which helps explain the alternate spellings -- when words are transliterated from a language that isn't spelled using the Latin alphabet, there will naturally be many possible transliterations, and several of them may end up being fully standard in English (cf. Chanukah / Hanukkah, tsar / czar, the umpteen spellings of Kaddafi, etc.)."
But, even though I'm no Molly Wyman (a resident expert on etymology), I'm going to say that "amok" should be used sometimes and "amuck" others. "Amok" originally comes from the Malay amoq: "engaging furiously in battle, attacking with desperate resolution, rushing in a state of frenzy to the commission of indiscriminate murder... Applied to any animal in a state of vicious rage."
Through the years, it seems, "amok" became confused with muck: "Excrement, manure; dirt, waste matter" (probably from early Scandinavian meaning dung). So running amok (engaging furiously in battle) also became to mean running amuck (running through excrement). What makes more sense: "The Davis campaign to retain his office is running amok [engaging furiously in battle]" or "The Davis campaign to retain his office is running amok [running through excrement {figuratively, of course}]"?
I'd say, use "amok" for the former and "amuck" for the later. Depending on what you mean to say.
UPDATE: Like many other things, I might just be all wrong about this. The Oxford Dictionary of American Usage and Style says: "Usage authorities once held firmly to the idea that amuck is preferable to amok—solely on the mistaken notion that amuck is older in English and amok (though a better transliteration of the Malaysian word) was a late-coming “didacticism.” In fact, both forms date from the 17th century. And, in any event, amok is ten times more common than amuck today—e.g.: “For decades, the Buildings Department, which processes 35, 000 permits a year, has resembled a satirist's vision of bureaucracy run amok” (N.Y. Times). But some publications fight the trend—as evidenced by the title of Charles Krauthammer's essay “Elephants Run Amuck: After Killing Big Government, the G.O.P. Suddenly Risks Stampeding Itself to Death” (Time). Amok is now the standard term." ("amok" The Oxford Dictionary of American Usage and Style. Bryan A. Garner. Oxford University Press, 2000. Oxford Reference Online. Oxford University Press. 13 August 2003