'ineffable' originates from Latin, specifically the word 'ineffabilis,' where 'in-' meant 'not' and 'effabilis' meant 'able to be spoken.'

'ineffabilis' transformed into the Old French word 'ineffable,' and eventually became the modern English word 'ineffable.'

Initially, it meant 'not able to be spoken,' but over time it evolved into its current meaning of 'too great to be expressed in words.'