SNAFU is an acronym for "situation normal, all f***ed up." This is usually softened to "situation normal, all fouled up" in reference to hardware, and in everyday usage. The acronym is sometimes used as a noun, for example, "This operation has turned into a big SNAFU."
The origin of this term is unknown. According to one story, U.S. combat officers in the Second World War began writing "SNAFU" in large, bold letters on forms they believed superfluous or irrelevant. They then returned the forms, otherwise blank, to the originating bureaucrats.
Compare FUBAR .