'argumentatory' originates from Latin, specifically the word 'argumentum', where the verb 'arguere' meant 'to make clear, to prove'.

'argumentatory' developed from Late Latin/Medieval Latin forms such as 'argumentatorius' and was adopted into English formation patterns (using the adjectival suffix '-atory').

Initially it related to 'pertaining to an argument or proof' in a formal, rhetorical sense; over time it also acquired the sense 'inclined to argue' (describing temperament or tone).