Definition of sludge in English:

Share this entry


Pronunciation: /ˈslʌdʒ/


[mass noun]
1Thick, soft, wet mud or a similar viscous mixture of liquid and solid components, especially the product of an industrial or refining process: the dumping of sewage sludge [count noun]: miscellaneous chemicals and treated sludges
More example sentences
  • He dismissed as ‘scaremongering’ the claims that chemical and industrial sludges were being processed in the plant or that animal and body parts were being processed.
  • Incinerators are designed to destroy gases, liquids, solids, sludges, and slurries at high temperatures.
  • Methods include in situ and ex situ treatment of contaminated soil, groundwater, industrial wastewater, sludges, soil slurries, marine oil spills, and vapour-phase effluvia.
sediment, lees, dregs, deposit, grounds, settlings, precipitate, residue;
Scottish & Northern English  clart;
Irish  slob
informal gunk, crud, gloop, grunge, gook, goo
British informal gunge, grot
North American informal guck, glop
rare grouts
1.1Dirty oil, especially in the sump of an internal combustion engine.
Example sentences
  • With the trowel, I commenced scooping diesel oil sludge into the bucket.
  • It's almost amusing, until one of them sinks into a pool of oily sludge and wings greased, struggles helplessly to get free as the others fly off.
  • It's like dumping fresh oil on sludge and wondering why your engine isn't running better!
2 [usually as modifier] An unattractive muddy shade of brown or green: a sludge green
More example sentences
  • Lunch is a revolting sludge burger in a pretty rustic restaurant, but Zoe thinks it's all marvellously delicious.
  • But won't that just reduce everything to a nasty green/purple sludge?
  • I can make do with that, if we mix it with a caffeine-sugar sludge combo.
3Sea ice newly formed in small pieces.



Pronunciation: /ˈslʌdʒi/
adjective (sludgier, sludgiest)
Example sentences
  • They've stripped the ceiling back to reveal the girders and piping, like some dated metropolitan style bar, yet they've kept the chandelier and the flock wallpaper and painted everything else an undistinguished sludgy brown.
  • One afternoon, we walked in to find her standing on the battered old dining room table, painting the ceiling a sludgy shade of snot green.
  • One's foot gladly sinks into the sludgy marsh.


Early 17th century: of uncertain origin; compare with slush.

Words that rhyme with sludge

adjudge, begrudge, bludge, budge, drudge, fudge, grudge, judge, misjudge, nudge, pudge, smudge, trudge

For editors and proofreaders

Line breaks: sludge

Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.