The verb negotiate didn't appear until the late sixteenth century, but the noun negotiation dates back to the early fifteenth. This, through Old French negociacion, comes from Latin negationem, which meant "to do business"- a little broader than the current definition. We can simplify that to negotium, meaning "business" or "affair" in general. Here it gets interesting: negotium to the roots nec, meaning "not", and otium, meaning "leisure". Therefore, Latin business was given the distinction of not being recreational. Nec is an apocope (simplification) of an earlier Latin word, neque, which in turn is a portmanteau of ne, meaning "not" (and coming from the Proto-Indo-European reconstruction ne), and the suffix -que, meaning "and" (from PIE kwe, same definition). Otium has an uncertain etymology, but it may trace to a Proto-Indo-European word for "forlorn". Negotiate and negotiation have about the same usage levels in the English language, each around 0.001%, and rising. I guess there's not a lot of leisure going on these days.
Hello! I'm Adam Aleksic, a sophomore studying linguistics and government at Harvard University, where I founded the Harvard Undergraduate Linguistics Society. I also have disturbing interests in politics, vexillology, geography, board games, conlanging, and law.