Etymology
1. c.1300, cognate with and probably from M.L.G.
mudde, M.Du.
modde "thick mud," from P.Gmc.
*mud- from PIE
*meu-/*mu-, found in many words denoting "wet" or "dirty" (cf. Gk.
mydos "damp," Pol.
mul "slime," Skt.
mutra- "urine," Avestan
muthra- "excrement, filth"); related to Ger.
schmutz "dirt," which also is used for "mud" to avoid
dreck, which originally meant "excrement." Replaced native fen (It., Sp.
fango, Fr.
fange are Gmc. loan-words). Meaning "lowest or worst of anything" is from 1586. As a word for "coffee," it is hobo slang from 1925. To
throw or
hurl mud "make disgraceful accusations" is from 1762. To say
(one's) name is mud and mean "(one) is discredited" is first recorded 1823, from
mud in obs. sense of "a stupid twaddling fellow" (1708).
Muddy (adj.) first recorded 1526; as a verb meaning "to make muddy," it is from 1601.
Big Muddy in ref. to the Missouri or Mississippi rivers is first recorded 1825.
2. From Middle English mud, mudde, mode, probably a borrowing from Middle Dutch mod, modde or Middle Low German mudde, ultimately from Proto-Germanic *mud-, *mudra- (“mud”), perhaps from Proto-Indo-European *mū-, *mew- (“moist”). Cognate with Saterland Frisian Mudde (“mud”), Middle High German mot (“mud”), Swedish modd (“slush”). Compare also suffixed variants English mother (“vinegar-forming sediment in alcohol”), West Frisian modder (“mud”), Dutch modder (“mud”), German Low German Mudder (“mud”), German Moder (“moldiness, mildew, decay”), Danish mudder (“mud”). Alternative etymology suggests the Proto-Germanic word is possibly borrowed from a Uralic language (compare e.g. Finnish muta (“mud”), Northern Sami mođđi (“mud”), Erzya мода (moda, “earth, ground”) from Proto-Uralic *muďa (“earth”)). See: Frisian, Saterlandic 'Mudde', Finnish with old forms '
muta'.