slough
Snakes in the slough slough their old skins each spring.
The first 'slough' is a noun pronounced /slaʊ/ (rhyming with 'cow'): a swamp or muddy backwater where the snakes live. The second is a verb pronounced /slʌf/ (rhyming with 'rough'): to shed or cast off an outer layer. Placing the two side by side makes the reader stumble exactly where the spelling stops predicting the sound, a small demonstration of why '-ough' is English's most notorious letter cluster.
Meanings
A wet, muddy hollow or a stretch of swampy backwater; figuratively, a state of hopeless dejection one cannot easily climb out of.
- The heron waded through the shallow slough at dusk.
- After the layoffs he sank into a slough of self-doubt.
To shed or cast off a dead outer layer such as skin; by extension, to discard something no longer wanted.
- The python will slough its skin in one long piece.
- She tried to slough off the habits of her old job.
Word origin
The swamp word is native: Old English 'slōh' (a muddy place), of uncertain deeper origin. The shedding word arrived separately in Middle English as 'slughe' or 'slouh', a noun for a snake's cast skin, probably related to Middle High German 'slūch' (snakeskin); the verb sense of shedding grew out of that noun centuries later. The two converged on one spelling while keeping different vowels.
Fun fact
'Slough' alone covers several of the '-ough' pronunciations: /slaʊ/ like 'bough' for the swamp (and for the English town of Slough), /slʌf/ like 'rough' for shedding, and in much of the United States /sluː/ like 'through' for a marshy inlet. John Bunyan's 1678 'Slough of Despond' in The Pilgrim's Progress is the source of the figurative 'slough' of despair.