The Spanish word 'argumentativo' (meaning 'argumentative') comes from the Latin 'argumentativus'. This Latin word was formed by combining 'argumentum' (meaning 'proof' or 'evidence') with the suffix '-ivus' (meaning 'relating to'). Going further back, 'argumentum' itself was created from the Latin verb 'arguere' (meaning 'to make clear' or 'to prove') plus the suffix '-mentum' (indicating a result or means). So literally, the word developed from elements meaning 'relating to the means of making something clear.'

Some simpler related Spanish words include 'argumento' (argument, plot), 'argumentar' (to argue), and 'argüir' (to argue or deduce). All these words share the same Latin root 'arguere' and maintain the core concept of presenting evidence or making a point clear, though 'argumentativo' specifically describes someone or something characterized by arguing or debating.

English speakers can easily connect 'argumentativo' with the English word 'argumentative', as they're direct cognates. Other related English words include 'argument', 'argue', and even 'arguable'. All these words come from the same Latin root 'arguere'. While the original meaning was about making something clear or proving a point, these words have evolved to be more associated with disagreement and debate in both languages.