WordNet records no synonym and no antonym for hannibal. 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.
general who commanded the Carthaginian army in the second Punic War; crossed the Alps and defeated the Romans but was recalled to defend Carthage and was defeated (247-182 BC)
a town in northeast Missouri on the Mississippi River; boyhood home of Mark Twain
Synonyms, antonyms and the broader and narrower relations for hannibal come from Princeton University’s WordNet. Full sources and licences.