[German FidoNet] German acronym for Dmmster Anzunehmender User (stupidest imaginable user). From the engineering-slang GAU for Grsster Anzunehmender Unfall, worst assumable accident, esp. of a LNG tank farm plant or something with similarly disastrous consequences. In popular German, GAU is used only to refer to worst-case nuclear accidents such as a core meltdown. See cretin, fool, loser and weasel.