Argumentative
late Middle English: from Old French argumentatif, -ive or late Latin argumentativus, from argumentari ‘conduct an argument’.
wiktionary
From Late Middle English argumentatif(“syllogistic, sophistic”), [1] from Old French argumentatif, argumentative (modern French argumentatif(“argumentative”)) and Medieval Latin, Late Latin argūmentātīvus, [2] from Latin argūmentātor + -īvus(suffix forming adjectives). Argūmentātor is the second-person singular future active imperative of argūmentor(“to prove, reason; to adduce something as an argument or proof; to conclude”), from argūmentum(“argument for a position; evidence, proof”) (from arguō(“to show; to prove; to assert, declare; to make clear”) (possibly ultimately from Proto-Indo-European *h₂erǵ-(“white, argent; glittering”)) + -mentum(suffix indicating the result of something)) + -or.
etymonline
argumentative (adj.)
mid-15c., "pertaining to arguments," from Old French argumentatif "able to argue or reason well," or directly from Medieval Latin argumentat-, past participle stem of argumentari "adduce proof, draw a conclusion," from argumentum (see argument) + -ive. Meaning "fond of arguing" is recorded from 1660s. Related: Argumentatively; argumentativeness.
