slough1 Syllabification: (slough)Pronunciation: /slou, slo͞o/Definition of slough noun 1a swamp. a side channel or inlet, or a natural channel that is only sporadically filled with water. 2a situation characterized by lack of progress or activity:the economic slough of the interwar yearsDerivatives sloughy adjective Origin: Old English slōh, slō(g), of unknown originslough in other Oxford dictionaries Definition of slough in the British & World English dictionary