'irrefutably' originates from Latin, specifically the word 'irrefutabilis,' where 'in-' meant 'not' and 'refutabilis' meant 'able to be refuted.' 'Assembled' comes from Old French 'assembler,' meaning 'to bring together.'

'irrefutabilis' transformed into the French word 'irrefutable,' and eventually became the modern English word 'irrefutable.' 'Assembler' transformed into the English word 'assemble.'

Initially, 'irrefutably' meant 'not able to be refuted,' and this meaning has largely remained the same in modern usage. 'Assemble' originally meant 'to bring together,' which is consistent with its current meaning.