Slough1, n.
(slou), n. [A-S. slôg, a hollow place, O. Ger. schlauch, an abyss, whirlpool, Gael. & Ir. sloc, slochd, a pit, pool, ditch, W. yslwch, a slough.] A place of deep mud or mire; a hole full of mire. “He's here stuck in a slough.” Milton.