Slough (noun)

1. A swampy or marshy area, especially one that is stagnant and covered with dead plant matter.
2. A place of deep mud or mire.
3. The cast-off skin or outer layer of a reptile or other animal.
4. A place or situation of deep despair or depression.

Origin:

Derived from the middle english word 'slouh', meaning a marsh, swamp, or stagnant pool.

Examples:

1. The herons and other wading birds can often be found hunting for food in the slough.
2. He got stuck in the slough and had to be rescued.
3. The snake had shed its slough, revealing its new and shiny skin.
4. She felt trapped in the slough of despair, unable to see a way out of her problems.
5. The area around the river was a slough, dotted with dead trees and murky water.