slough

1. A marshy or muddy area.
2. 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. A secondary channel of a river delta, usually flushed by the tide. (US) · 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. A small pond, often alkaline, many but not all formed by glacial potholes.

Plural sloughs