'squalid' originates from Latin, specifically the word 'squalidus,' where 'squal-' meant 'rough or dirty.'

'squalidus' transformed into the French word 'squalide,' and eventually became the modern English word 'squalid' through Middle English.

Initially, it meant 'rough or dirty,' but over time it evolved into its current meaning of 'extremely dirty and unpleasant.'