'insoluble' originates from Latin, specifically the word 'insolubilis,' where 'in-' meant 'not' and 'solubilis' meant 'able to be loosened or dissolved.'

'insolubilis' transformed into the Old French word 'insoluble,' and eventually became the modern English word 'insoluble' through Middle English.

Initially, it meant 'not able to be dissolved,' but over time it evolved to also mean 'not able to be solved.'