WordNet records no synonym and no antonym for arbitrage. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a kind of hedged investment meant to capture slight differences in price; when there is a difference in the price of something on two different markets the arbitrageur simultaneously buys at the lower price and sells at the higher price
practice arbitrage, as in the stock market
Synonyms, antonyms and the broader and narrower relations for arbitrage come from Princeton University’s WordNet. Full sources and licences.