'refutatory' originates from Latin, specifically the verb 'refutare', where 're-' meant 'back' and the stem conveyed the idea of driving off or repelling.

'refutare' passed into Medieval Latin as 'refutatorius' (meaning 'serving to refute') and was later adopted into English as the adjective 'refutatory' via regular Late Latin/Medieval Latin formation with the suffix '-ory'.

Initially it carried the basic sense 'to drive back or repel (an attack or argument)'; over time it evolved into the more specific modern sense 'tending to refute or disprove an argument'.