'debatably' originates from the word 'debatable', which comes from the Old French word 'debatre', meaning 'to fight or contend'.

'debatre' transformed into the Middle English word 'debaten', and eventually became the modern English word 'debatable', from which 'debatably' is derived.

Initially, it meant 'to fight or contend', but over time it evolved into its current meaning of 'open to discussion or argument'.