'argumentativeness' originates from English, specifically formed from the adjective 'argumentative' plus the noun-forming suffix '-ness'. 'Argumentative' itself ultimately derives from Latin 'argumentum' (via Old French/Latin), where the root 'arguere' meant 'to make clear, to accuse'.

'argumentativeness' developed from the adjective 'argumentative' (formed in modern English from 'argument' + '-ative'), with 'argument' coming from Latin 'argumentum' through Old French and Middle English; the modern noun was created by adding '-ness' to the adjective to indicate a state or quality.

Originally, the Latin 'argumentum' meant 'evidence' or 'that which makes clear'; over time the related English words came to refer to 'a reasoned discussion' and then to personal tendency to argue — thus 'argumentativeness' now means a disposition toward arguing.