slough

Etymology 1

From Middle English slogh, slugh, slouh, from Proto-Germanic *sluk-, perhaps related to *sleupaną (“to slip, sneak”) (compare Gothic 𐍃𐌻𐌹𐌿𐍀𐌰𐌽 (sliupan)). Akin to Middle Low German slô (“sheath, skin on a hoof”). Perhaps also related with Old Saxon slūk (“snakeskin”), Middle High German slūch, whence German Schlauch (“waterskin, hose”).

noun

1. The skin shed by a snake or other reptile.
   That is the slough of a rattler; we must be careful.
2. Dead skin on a sore or ulcer.
   This is the slough that came off of his skin after the burn.

verb

1. (transitive) To shed skin or outer layers.
   This skin is being sloughed.
   Snakes slough their skin periodically.
2. (intransitive) To slide off or flake off, as an outer layer, such as skin, might do.
   A week after he was burned, a layer of skin on his arm sloughed off.
   The mud sloughed off her palms easily […] 2013, Casey Watson, Mummy’s Little Helper: The heartrending true story of a young girl
   1944 United States. Bureau of Mines · War Minerals Report 386. Google books The adit penetrated the vug ... and at this level ... it was filled with material that had ... sloughed off the walls.
   An avalanche sloughing off a Utah mountainside killed a state Department of Transportation avalanche forecaster while he was surveying snow levels near a popular winter recreation area, authorities reported. April 13, 2013, Michael Mello, “Avalanche forecaster killed in Utah avalanche”, in Los Angeles Times
3. (transitive, card games) To discard.
   East sloughed a heart.
4. (intransitive, slang, Western US) To commit truancy, be absent from school without permission.

Etymology 2

From Old English slōh, probably from Proto-Germanic *slōhaz.

noun

1. (Britain) A muddy or marshy area.
2. (Eastern United States) A type of swamp or shallow lake system, typically formed as or by the backwater of a larger waterway, similar to a bayou with trees.
   We paddled under a canopy of trees through the slough.
3. (Western United States) A secondary channel of a river delta, usually flushed by the tide.
   The Sacramento River Delta contains dozens of sloughs that are often used for water-skiing and fishing.
4. A state of depression.
   John is in a slough.
5. (Canadian Prairies) A small pond, often alkaline, many but not all formed by glacial potholes.
   Potholes or sloughs formed by a glacier’s retreat from the central plains of North America, are now known to be some of the world’s most productive ecosystems.