See more synonyms for muck on
  1. moist farmyard dung, decaying vegetable matter, etc.; manure.
  2. a highly organic, dark or black soil, less than 50 percent combustible, often used as a manure.
  3. mire; mud.
  4. filth, dirt, or slime.
  5. defamatory or sullying remarks.
  6. a state of chaos or confusion: to make a muck of things.
  7. Chiefly British Informal. something of no value; trash.
  8. (especially in mining) earth, rock, or other useless matter to be removed in order to get out the mineral or other substances sought.
verb (used with object)
  1. to manure.
  2. to make dirty; soil.
  3. to remove muck from (sometimes followed by out).
  4. Informal.
    1. to ruin; bungle (often followed by up).
    2. to put into a state of complete confusion (often followed by up).
Verb Phrases
  1. muck about/around, Informal. to idle; waste time; loiter.

Origin of muck

1200–50; Middle English muc, muk < Old Norse myki cow dung


noun Informal.
  1. a bungled or disordered situation; foul-up.

Origin of muck-up

First recorded in 1925–30; noun use of verb phrase muck up Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for muck up

muck up

verb (adverb) informal
  1. (tr) British and Australian to ruin or spoil; make a mess of
  2. (intr) Australian to misbehave


  1. farmyard dung or decaying vegetable matter
  2. Also called: muck soil an organic soil rich in humus and used as a fertilizer
  3. dirt or filth
  4. earth, rock material, etc, removed during mining excavations
  5. slang, mainly British rubbish
  6. See Lord Muck, Lady Muck
  7. make a muck of slang, mainly British to ruin or spoil
verb (tr)
  1. to spread manure upon (fields, gardens, etc)
  2. to soil or pollute
  3. (often foll by out) to clear muck from

Word Origin for muck

C13: probably of Scandinavian origin; compare Old Norse myki dung, Norwegian myk
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for muck up



mid-13c., "cow dung and vegetable matter spread as manure," from a Scandinavian source, cf. Old Norse myki, mykr "cow dung," Danish møg, from Proto-Germanic *muk-, *meuk- "soft." Meaning "unclean matter generally" is from c.1300. Muck-sweat first attested 1690s.



late 14c., "to dig in the ground," also "to remove manure," early 15c., "to spread manure, cover with muck," from muck (n.). Meaning "to make dirty" is from 1832; in the figurative sense, "to make a mess of," it is from 1886; to muck about "mess around" is from 1856. Related: Mucked; mucking.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with muck up

muck up

Bungle, damage, make a mess of, as in Don't let him write the review; he's sure to muck it up. This idiom alludes to the verb muck in the sense of “spread manure on.” [Early 1900s] For a synonym, see foul up.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.