slew / slough / slue are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
slew: NA
slough: (noun) a hollow filled with mud. (noun) a stagnant swamp (especially as part of a bayou). (noun) any outer covering that can be shed or cast off (such as the cast-off skin of a snake).
slue: NA
slew: s·l·UW
slough: s·l·AH·f
slue: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)