One is discredited. This term apparently originated in the British Parliament in the early nineteenth century, when it was used for any member who disgraced himself, through either a singularly bad speech or an overwhelming defeat in an election. (In the eighteenth and nineteenth centuries mud was slang for “a fool” or “a stupid fellow.”) Some ascribe the usage to Dr. Samuel Mudd, who helped John Wilkes Booth escape after assassinating President Lincoln. Apart from the different spelling, this derivation is a bit of folklore. Actually, “mud” was defined as a “stupid, twadding fellow” in a slang dictionary of 1823, which also stated “And his name is mud” was pronounced after a silly speech. Even earlier, “mud” was defined as a fool or thick-skulled fellow (in Hell upon Earth, 1703). In time, however, the meaning became milder, simply denoting that someone had made a bad mistake.