'arguably' originates from the word 'arguable', which is derived from the Latin word 'arguere', meaning 'to make clear, prove, or accuse'.

'arguere' transformed into the Old French word 'arguer', and eventually became the modern English word 'argue', from which 'arguable' and 'arguably' are derived.

Initially, it meant 'to make clear or prove', but over time it evolved into its current meaning of 'open to argument or debate'.