sludge

noun

1. (countable, uncountable)Solids separated from suspension in a liquid.

   “Floods in northern India, mostly in the small state of Uttarakhand, have wrought disaster on an enormous scale.[…]Rock-filled torrents smashed vehicles and homes, burying victims under rubble and sludge.”

2. (countable, uncountable)A residual semi-solid material left from industrial, water treatment, or wastewater treatment processes.
3. (countable, uncountable)A sediment of accumulated minerals in a steam boiler.
4. (countable, uncountable)A mass of small pieces of ice on the surface of a water body.
5. (abbreviation, alt-of, ellipsis, uncountable)Ellipsis of sludge metal.
6. (countable, uncountable)Institutional policies that introduce tedium and inefficiency in processes.

   “In the 2008 best seller Nudge, the legal scholar Cass R. Sunstein and the economist Richard H. Thaler marshaled behavioral-science research to show how small tweaks could help us make better choices. An updated version of the book includes a section on what they called “sludge”—tortuous administrative demands, endless wait times, and excessive procedural fuss that impede us in our lives.”

7. (mnemonic)An acronym used to help remember the common symptoms of certain affections of a cholinergic toxidrome: salivation, lacrimation, urination, defecation, gastrointestinal upset, emesis.

verb

1. (informal, intransitive)To slump or slouch.
2. (intransitive)To slop or drip slowly.